First FRCR Anatomy: Practice Cases Constantinos Tingerides, Ashley Uttley, David Minks, Claire Exley
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Head and neckChapter 1

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Case 1.1
Case 1.1
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.1
  1. Rostrum of the corpus callosum
  2. Genu of the corpus callosum
  3. Body of the fornix
  4. Splenium of the corpus callosum
  5. Mamillary body of the hypothalamus
Midline sagittal MRI of the brain.
The corpus callosum lies in the depths of the great longitudinal fissure (interhemispheric fissure). It is composed of commissural fibres that unite corresponding regions of the two cerebral hemispheres. In this image we can identify the major parts of the corpus callosum. From rostral to caudal these are: rostrum, genu, body and splenium.
The fornix is a C-shaped fascicle of fibres that links the hippocampus with the mamillary body of the hypothalamus. The horizontal bundles of fibres that come together in the midline form the body of the fornix. The upper surface of this structure provides attachments to the septum pellucidum, a membrane that separates the anterior horns of the lateral ventricles.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
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Case 1.2
Case 1.2
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.2
  1. Anterior pituitary (adenohypophysis)
  2. Infundibulum
  3. Interpeduncular cistern
  4. Body of corpus callosum
  5. Pineal gland
Midline sagittal MRI of the brain.
The pituitary gland is a pea-sized structure that sits in the sella turcica of the sphenoid bone. It consists of the posterior pituitary (neurohypophysis) and the anterior pituitary (adenohypophysis). The posterior pituitary is a neuronal structure and can be considered as an expansion of the distal part of the infundibulum (pituitary stalk). On a T1-weighted MRI such as this one, the posterior pituitary is bright (high signal). This helps to identify it with confidence. The anterior pituitary is larger.
The interpeduncular cistern is located at the base of the brain, spanning the space between the temporal lobes. It is deepest between the cerebral peduncles of the midbrain, hence the name. It contains the optic chiasm where the optic nerves partially cross.
The pineal gland (also called pineal body) lies in the midline immediately rostral to the superior colliculi of the midbrain. It is part of the epithalamus which is one of the four main subdivisions of the diencephalon. The hypothalamus is the most ventral part of the diencephalon and lies inferior to the thalamus and ventromedial to the subthalamus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
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Case 1.3
Case 1.3
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.3
  1. Clivus
  2. Optic chiasm
  3. Cingulate gyrus
  4. Massa intermedia of thalami
  5. Tonsil of cerebellum
Midline sagittal MRI of the brain.
The clivus (Latin for ‘slope’) is a shallow depression behind the dorsum sellae. It forms a sloping process at the junction of the occipital and sphenoid bones. The optic chiasm is where half of the fibres of the optic nerve cross to the other side. A mass in the pituitary or the suprasellar fossa can compress this structure. The cingulate gyrus lies above the corpus callosum. It is considered as part of the limbic system and it is thus separate to the frontal and parietal lobes. The thalamus resembles a small hen's egg. Together with the hypothalamus, it forms the lateral wall of the third ventricle. The cerebellar tonsils are the most antero-inferior part of the cerebellar hemispheres. They lie close to the midline and therefore can be seen in a midline sagittal image.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
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Case 1.4
Case 1.4
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.4
  1. Pons
  2. Ventral midbrain (tegmentum)
  3. Quadrigeminal plate (tectum)
  4. 4th ventricle
  5. Medulla oblongata
Midline sagittal MRI of the brain.
The brainstem connects the cerebral hemispheres with the spinal cord. It consists of three parts: the midbrain, the pons and the medulla.
The midbrain is the most superior part of the brainstem. The quadrigeminal plate is the dorsal part of the midbrain. It is also referred to as tectum (Latin for ‘roof’). It is separated from the ventral midbrain (tegmentum) by the cerebral aqueduct (aqueduct of Sylvius), which connects the 3rd and 4th ventricles.
The pons is the widest part of the brainstem. It has a bulbous anterior part. Its posterior part forms the upper part of the floor of the 4th ventricle. The lower part of the floor of the 4th ventricle is formed by the posterior surface of the medulla.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
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Case 1.5
Case 1.5
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.5
  1. Cisterna magna
  2. Pontine cistern
  3. Suprasellar cistern
  4. Interpeduncular cistern
  5. Quadrigeminal cistern
Midline sagittal MRI of the brain.
The subarachnoid space is deep in several places, particularly around the base of the brain. These spaces are referred to as subarachnoid cisterns and are named according to nearby structures. The cistern magna lies below the cerebellar hemispheres and behind the medulla. The pontine cistern lies between the pons and the clivus. The interpeduncular cistern lies between the temporal lobes and is widest between the cerebral peduncles of the midbrain.
The quadrigeminal cistern lies posterior to the quadrigeminal plate, between the splenium of the corpus callosum and the vermis of the cerebellum. The suprasellar cistern lies above the pituitary fossa. It is continuous posteriorly with the quadrigeminal cistern.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 74.
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Case 1.6
Case 1.6
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.6
  1. Right central sulcus
  2. Right precentral gyrus
  3. Right superior frontal sulcus
  4. Left postcentral gyrus
  5. Superior sagittal sinus
Axial MRI through the central sulcus.
The central sulcus (or Rolandic fissure) separates the frontal from the parietal lobe in each hemisphere. It runs in the near coronal plane. Anterior to the central sulcus lies the precentral gyrus which contains the primary motor cortex. Posterior to the central sulcus lies the postcentral gyrus or primary somatosensory cortex.
The superior frontal sulcus runs in the sagittal plane and separates the superior and middle frontal gyri. The posterior end of the superior frontal sulcus forms at right angles with the precentral sulcus. Identifying the precentral sulcus allows us to identify the central sulcus as it is the sulcus immediately posterior to it.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 46.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge University Press, 1999: 43.
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Case 1.7
Case 1.7
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.7
  1. Right lentiform nucleus
  2. Head of the right caudate nucleus
  3. Anterior horn of the right lateral ventricle
  4. Interhemispheric fissure
  5. Anterior limb of the left internal capsule
Axial MRI of the brain at the level of the lateral ventricles.
This axial section and the midline sagittal MRI must be studied in detail. They contain key anatomical structures and are always likely to feature in the exam. These structures should be studied in sagittal and coronal images to begin to form a three dimensional understanding of brain anatomy.
Within the cerebral hemispheres lie a number of nuclear masses collectively known as basal ganglia. The major components are the caudate nucleus, the putamen and the globus pallidus. For anatomical purposes, the putamen and globus pallidus are together called lentiform or lenticular nucleus. The putamen lies lateral to the globus pallidus.
The anterior limb of the internal capsule separates the lentiform nucleus from the head of the caudate nucleus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
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Case 1.8
Case 1.8
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.8
  1. Interhemispheric fissure
  2. Right insular cortex
  3. Splenium of corpus callosum
  4. Left tapetum
  5. Posterior limb of the internal capsule
Axial MRI of the brain at the level of the lateral ventricles.
The Sylvian fissure (or lateral sulcus) separates the frontal from the temporal lobes.
Lateral to the putamen, there is a thin sheet of grey matter known as the claustrum. It is sandwiched between two layers of white matter: the external capsule medially and the extreme capsule laterally. Lateral to the extreme capsule and in the floor of the lateral sulcus, lies the cortex referred to as the insula (of Reil).
The left and right cerebral hemispheres fill the cranial vault above the tentorium cerebelli. They are connected in the midline by the corpus callosum which lies deep in the interhemispheric fissure (median longitudinal fissure). The corpus callosum is a large mass of commissural fibres. The genu is its most anterior part. Fibres extending laterally from the body of the corpus callosum are called the tapetum. They form part of the roof and lateral wall of the lateral ventricle.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
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Case 1.9
Case 1.9
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.9
  1. Right thalamus
  2. Posterior limb of the internal capsule (right)
  3. Anterior horn of the right lateral ventricle
  4. Septum pellucidum
  5. Choroid plexus (left)
Axial CT of the brain at the level of the basal ganglia.
This axial image is at the same level as the image in the previous case. It is, however, a different modality. T1-weighted MRIs can show the anatomy very clearly but CTs of the brain may be used in the exam. Make sure that you are comfortable with both modalities.
The windowing in this image has been set to optimise the appearance of brain parenchyma. The cortical and deep grey matter appears brighter than the white matter.
The thalamus is separated from the lentiform nucleus by the posterior limb of the internal capsule.
The septum pellucidum is a thin triangular membrane that separates the anterior horn of the lateral ventricles. Anatomical variants are common in this structure and you should be familiar with them.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
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Case 1.10
Case 1.10
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.10
  1. Fourth ventricle
  2. Right flocculus
  3. Right middle cerebellar peduncle
  4. Right cerebellar hemisphere
  5. Left cerebellopontine angle cistern
Axial MRI at the level of the fourth ventricle.
On axial imaging, the lower pons is dominated by the posterolaterally directed middle cerebellar peduncles. Lateral to these structures lie the cerebellopontine angle cisterns which are limited posteriorly by the flocculi, a pair of small cerebellar lobes.
The fourth ventricle has a ‘roof’ dorsally and a ‘floor’ ventrally. The roof is formed by the cerebellum and the floor by the pons and medulla. The lateral walls are formed by the cerebellar peduncles. Study these structures in the midline sagittal images to form a three dimensional understanding.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 42.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 55.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 32.
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Case 1.11
Case 1.11
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.11
  1. Right cingulate gyrus
  2. Optic chiasm
  3. Left internal carotid artery
  4. Right Sylvian fissure
  5. Sphenoidal sinus
Coronal T1-weighted MRI of the brain.
In this image we see the internal carotid artery in the cavernous sinus. Note that on a T1-weighted MRI, rapidly flowing blood is displayed as black signal voids. The internal carotid artery is a branch of the common carotid artery and receives 70% of its blood flow. It arises approximately at the level of the C3 vertebral body and enters the skull through the carotid canal. This marks the onset of the petrous segment. It passes through the foramen lacerum where the laceral segment begins. It is a short segment and it ends at the petrolingual ligament, where the cavernous segment begins. The cavernous segment ends at the proximal dura ring.
The optic chiasm is where the optic nerves partially cross. It lies anterior to the pituitary stalk and superomedially to the cavernous sinuses. The body of the sphenoid bone contains the sphenoidal sinuses which provide a route for surgical access to the pituitary gland via the nose.
By reviewing the coronal images we can appreciate the sylvian fissure separates the superior surface of the temporal lobe from the anterior surface of the frontal lobe and the anterior surface of the parietal lobe.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 48-49.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 59.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 45.
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Case 1.12
Case 1.12
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.12
  1. Right hippocampus
  2. Fornix
  3. Third ventricle
  4. Pons
  5. Left external acoustic meatus
Coronal T1-weighted MRI of the brain.
The limbic system is composed of functionally related structures which surround the corpus callosum at the medial surface of the cerebral hemispheres. You may be asked to identify parts of the limbic system such as the cingulate, splenial and parahippocampal gyri, the hippocampus, the dentate gyrus and the fornix. It is worth spending some time studying diagrams of the limbic system and reviewing its appearance on coronal and parasagittal MRIs.
The thalami are bodies of grey matter that lie in the lateral walls of the third ventricle. The external acoustic (or auditory) meatus is part of the external ear. It is a tube that runs medially to the tympanic membrane.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 48-49.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 59.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 45.
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Case 1.13
Case 1.13
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.13
  1. Right internal carotid artery (cervical segment)
  2. Right internal carotid artery (petrous segment)
  3. Right internal carotid artery (cavernous segment)
  4. Right middle cerebral artery
  5. Right anterior cerebral artery
Magnetic resonance angiography-coronal view.
The internal carotid artery arises from the common carotid artery and lies posterolateral to the external carotid artery. No branches arise from the common carotid artery or the cervical segment of the internal carotid artery.
The internal carotid artery enters the skull through the carotid canal. That is where the petrous segment begins. The course here is anteromedial and horizontal as it can be seen in this image. The artery then turns superiorly and enters the cavernous sinus. At this point the cavernous segment begins. Note the siphon shape that the artery assumes in this segment. Emerging from the cavernous sinus the artery divides into its terminal branches: the anterior cerebral artery and the middle cerebral artery.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
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Case 1.14
Case 1.14
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.14
  1. Right anterior cerebral artery
  2. Left vertebral artery
  3. Right middle cerebral artery
  4. Left internal carotid artery
  5. Posterior cerebral artery
Magnetic resonance angiography-axial view.
The circle of Willis lies in the suprasellar cistern. It is formed by links between the internal carotid arteries and the vertebrobasilar system. The single anterior communicating artery links the two anterior cerebral arteries. There are two posterior communicating arteries, one on each side, that link the internal carotid artery with the vertebrobasilar system. The circle of Willis is not circular in shape but rather is star-shaped (Figure 1.1). It is complete in only a minority of individuals so do not be thrown by a missing branch.
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Figure 1.1: The circle of Willis.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
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Case 1.15
Case 1.15
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.15
  1. Basilar artery
  2. Internal carotid artery
  3. Posterior cerebral artery
  4. Posterior communicating artery
  5. Ophthalmic artery
Magnetic resonance angiography-lateral view.
In this image we see the same vessels as in the previous two images but from the side. On lateral images such as this one and on some catheter angiograms, it is not possible to accurately determine laterality. If that is the case, simply name the vessel rather than guessing the side.
The ophthalmic artery is the first branch of the internal carotid artery distal to the cavernous sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
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Case 1.16
Case 1.16
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.16
  1. Petrous part of the internal carotid artery
  2. Cavernous part of the internal carotid artery
  3. Middle cerebral artery
  4. Anterior cerebral artery (A1 segment)
  5. Pericallosal artery (A3 segment)
Catheter angiogram of the carotid artery.
Catheter angiography is used for diagnosis and treatment of vascular problems in the brain. This is an image from an angiogram of the carotid artery.
The internal carotid artery is the biggest vessel and has a characteristic shape. The different segments of the artery are seen in this image, including the terminal branches of the internal carotid artery: the anterior and middle cerebral arteries. The anterior cerebral artery arises from the internal carotid artery at the anterior perforated substance. It is divided into segments:
  • A1 is the first segment and it extends from the origin to the level of the anterior communicating artery.
  • A2 begins after the anterior communicating artery and continues to the bifurcation of the artery into its terminal branches.
Two branches are given off in A2:
  • The orbital frontal artery is the first branch after the anterior communicating artery.
  • The frontopolar artery arises distal to the orbital frontal, close to where the artery loops over the genu.
After the artery loops over the genu, it passes posteriorly on the superior surface of the corpus callosum. At this point it bifurcates into the callosal marginal and the pericallosal artery (which forms the A3 segment).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
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Case 1.17
Case 1.17
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.17
  1. Vertebral artery
  2. Basilar artery
  3. Posterior communicating artery
  4. Posterior cerebral artery
  5. Superior cerebellar artery
Catheter angiogram of the vertebral artery.
The vertebral arteries are the first branches of the subclavian arteries on each side. They ascend the neck within the foramina transversaria. They pass through the foramen magnum to enter the skull. At that point they pierce the dura and enter the subarachnoid space. The left and right vertebral arteries join to form the basilar artery at the level of the pontomedullary junction. The posterior inferior cerebellar arteries (PICA) arise from the vertebral arteries just before they join. The anterior inferior cerebellar arteries (AICA) and the superior cerebellar arteries arise from the basilar artery.
In this image we see the left vertebral artery entering the skull and continuing as the basilar artery after joining with the right vertebral artery. The terminal branches are labelled: the posterior cerebral arteries and the posterior communicating arteries. Just before the basilar artery splits into the terminal branches, it gives off the superior cerebellar artery.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 38.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 85.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
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Case 1.18
Case 1.18
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.18
  1. Superior sagittal sinus
  2. Straight sinus
  3. Confluence of sinuses (torcular herophili)
  4. Transverse sinus
  5. Sigmoid sinus
Magnetic resonance venogram.
The venous drainage of the brain (Figure 1.2) does not follow the arterial supply. The venous sinuses are low pressure veins within folds of dura. The superior sagittal sinus begins anteriorly and runs to the back in the midline to the internal occipital protuberance. Posteriorly the sinus turns to one side (usually the right) and continues as the transverse sinus.
zoom view
Figure 1.2: Venous drainage of the brain-lateral view.
The inferior sagittal sinus runs in the lower free edge of the falx cerebri. Posteriorly it joins the great cerebral vein to become the straight sinus. The straight sinus then runs posteriorly to meet the sagittal sinus at the confluence of sinuses (torcular herophili). The transverse sinuses run on either side to the mastoid bone where they turn inferiorly and become the sigmoid sinuses. The transverse and sigmoid sinuses together are known as the lateral sinus. The sigmoid sinus continues through the jugular foramen as the internal jugular vein.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 39-41.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 87-90.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 57-58.
20
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Case 1.19
Case 1.19
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.19
  1. Inferior sagittal sinus
  2. Internal cerebral vein
  3. Basal vein of Rosenthal
  4. Great cerebral vein (of Galen)
  5. Internal jugular vein
Magnetic resonance venogram.
The internal cerebral veins run in the roof of the third ventricle on each side and unite under the splenium of the corpus callosum, to form the great cerebral vein of Galen. This is a short vein that passes posterosuperiorly behind the splenium to drain in the anterior end of the straight sinus where it unites with the inferior sagittal sinus.
The basal veins of Rosenthal begin at the anterior perforated substance by the union of the anterior cerebral vein, the deep middle cerebral vein and the striate veins. The basal veins of Rosenthal pass around the midbrain on each side to join the great cerebral vein of Galen (Figure 1.2).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 39-41.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 87-90.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 57-58.
21
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Case 1.20
Case 1.20
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.20
  1. Right superior rectus
  2. Right optic nerve
  3. Left superior oblique
  4. Left medial rectus
  5. Vomer
Coronal soft tissue CT through the orbits.
Six extrinsic ocular muscles insert into the sclera. The four rectus muscles arise from a common tendinous ring (annulus of Zinn) that surrounds the optic canal and part of the superior orbit fissure. They insert onto the globe anterior to the equator and have the following functions:
  • medial rectus rotates the pupil medially
  • lateral rectus rotates the pupil laterally
  • superior rectus rotates the pupil superiorly
  • inferior rectus rotates the pupil inferiorly
The superior oblique arises from the sphenoidal bone superomedial to the optic foramen. It passes through the trochlea to insert onto the upper outer surface posterior to the equator, directing the pupil inferiorly and laterally.
The inferior oblique arises from the orbital floor to insert onto the lower outer part posterior to the equator, directing the pupil laterally and superiorly.
The vomer forms the bony part of the nasal septum and separates the choanae.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 889.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 27.
22
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Case 1.21
Case 1.21
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.21
  1. Frontal sinus
  2. Hard palate
  3. Anterior arch of atlas
  4. Clivus
  5. Pituitary fossa
Lateral skull radiograph.
The frontal sinuses are often asymmetrical and lie between the inner and outer tables of the frontal bone above the nose and medial orbits. They are lined by mucus secreting epithelium, and drain through the frontonasal duct into the infundibulum, which opens into the semilunar hiatus of the middle meatus.
The palate forms the floor of the nasal cavities and the roof of the mouth. The hard (bony) palate is concave and formed from the palatine processes of the maxillae and the horizontal plates of the palatine bones.
The pituitary fossa is a depression in the sella turcica of the upper surface of the sphenoid bone in which the pituitary gland sits. The sella turcica is surrounded by the anterior and posterior clinoid processes (clinoid meaning ‘bedpost’) like the posts of a four poster bed. The posterior part of the sella turcica is the dorsum sellae, which is continuous with the clivus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 6.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 934, 957.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 4.
23
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Case 1.22
Case 1.22
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.22
  1. Sagittal suture
  2. Right lambdoid suture
  3. Right frontal sinus
  4. Left maxillary sinus
  5. Ramus of right mandible
Occipitofrontal skull projection.
The sagittal suture is in the midline between the two parietal bones. The two parietal bones are joined to the occipital bone by the lambdoid suture, which is often visible on an occipitofrontal projection. The frontal bones join the parietal bones at the coronal suture. The bregma is the junction between the coronal and sagittal sutures, and the lambda is the junction between the lambdoid and sagittal sutures (Figure 1.3).
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Figure 1.3: The cranial bones and sutures.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 2-6.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 5.
24
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Case 1.23
Case 1.23
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.23
  1. Right temporomandibular fossa
  2. Left mandibular notch
  3. Right angle of mandible
  4. Right coronoid process
  5. Right external acoustic meatus
Radiographs of both temporomandibular joints.
These are closed and open mouth plain radiographs of the temporomandibular joints.
On opening the mouth the mandibular condyle translates anteriorly. The next question explains the temporomandibular joints in more detail.
25
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Case 1.24
Case 1.24
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.24
  1. External auditory meatus
  2. Articular disc
  3. Condyle of mandible
  4. Temporal lobe
  5. Lateral pterygoid muscle
MRI of the temporomandibular joint (TMJ).
The TMJ is a synovial joint, of which the articular surfaces are the articular tubercle of the temporal bone, the mandibular fossa, and the condyle of the mandible (Figure 1.4). These articular surfaces are covered in fibrous cartilage.
The joint is separated into superior and inferior compartments (both have a separate synovial membrane) by the fibrocartilaginous disc. Translational movements occur in the superior compartment, rotational in the inferior compartment. The condyle of the mandible sits in the fossa at rest, and slides anteriorly on to the articular tubercle when open.
Muscles producing mandibular movements at the temporomandibular joints are given in Table 1.1.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 916.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 7.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 17-18.
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Figure 1.4: The temporomandibular joint.
Table 1.1   The types of mandibular movement at the temporomandibular joint and the muscles that control each one.
Mandibular movement
Muscles involved
Depression (open mouth)
• Suprahyoid
• Infrahyoid
• Lateral pterygoid
Protrusion
• Lateral pterygoid
• Masseter
• Medial pterygoid
Elevation (close mouth)
• Temporalis
• Masseter
• Medial pterygoid
Retrusion
• Temporalis
• Masseter
Lateral movement
• Retractors of same
• Protruders of opposite
26
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Case 1.25
Case 1.25
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.25
  1. Right lower second molar
  2. Left upper central incisor
  3. Floor of left maxillary sinus
  4. Left lower canine
  5. Hyoid bone
Orthopantomogram (OPG).
An OPG is a panoramic radiograph of the mandible and maxilla in order to image the dentition. It is acquired by rotating a horizontal arm from ear to ear. This means that the central hyoid bone is projected into both edges of the film.
One must not neglect to learn the teeth. OPGs are common examinations.
27
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Case 1.26
Case 1.26
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.26
  1. Upper left lateral incisor
  2. Lower left 2nd premolar
  3. Upper right 1st molar
  4. Lower right 3rd molar (Wisdom tooth)
  5. Lower right canine
Orthopantomogram (OPG).
There are 20 deciduous or milk teeth which usually begin erupting by 6 months of age. The symphysis menti fuses at 2 years of age. The permanent teeth develop in the maxilla and mandible during childhood, and are calcified by 3 years of age.
As the permanent teeth erupt, the roots of the deciduous teeth are resorbed. The medial teeth begin erupting before the lateral teeth, and the lower before the upper. The permanent teeth are present by 12-13 years of age, except the wisdom teeth (third molars) which erupt in early adulthood.
There are 20 deciduous teeth, and 32 permanent teeth. In each quadrant:
  • child: two incisors, one canine, two molars.
  • adult: two incisors, one canine, two premolars, three molars.
Supernumerary teeth can be seen on an OPG, and they characteristically occur lateral to the last tooth in each series.
At the centre of each tooth sits the radiolucent highly vascular pulp tissue, which is surrounded by a layer of dentine. Dentine comprises an organic and calcified structure, arranged in porous tubules, and has a radiographic density similar to compact bone. The exposed intraoral portion of each tooth (the crown) has an outer layer of enamel which comprises calcium hydroxyapatite crystals. This is densely radio-opaque. At the cementoenamel junction, which sits at the level of the alveolar ridge, the tooth is no longer covered with enamel, but with cementum. This cementum provides the surround to the root system.
The root and neck of the tooth are surrounded by the radiolucent periodontal membrane. The lamina dura is a dense line of bone which surrounds this and each root, and is continuous with the lamina dura of adjacent teeth (Figures 1.5 and 1.6).
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 19.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 34.
Weber E, Netter FH, Vilensky JA, Carmichael SW. Netter's Concise Radiologic Anatomy. Philadelphia: Saunders/Elsevier, 2009: 46.
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Figure 1.5: The anatomy of the tooth.
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Figure 1.6: The distribution of adult teeth.
28
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Case 1.27
Case 1.27
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.27
  1. Right zygomaticofrontal suture
  2. Frontal process of right zygoma
  3. Left lamina papyracea
  4. Nasal septum
  5. Left zygomatic arch
Occipitofrontal projection of facial bones.
The zygomatic/malar bone forms the prominence of the cheek, and articulates with the frontal, maxillary and temporal bones at the zygomaticofrontal, zygomaticomaxillary and zygomaticotemporal sutures respectively. It forms the boundary of the temporal fossa superiorly and the infratemporal fossa inferiorly.
The medial orbit of the wall is formed mainly from ethmoid bone, with contributions from maxillary, lacrimal and sphenoid bones. The paper thin bone separating the orbit from the ethmoid air cells is the lamina papyracea.
The nasal septum is part bony and part cartilaginous and divides the nasal cavity in two in the sagittal plane. The main contributors are:
  • perpendicular plate of ethmoid -descends from the cribriform plate to form the superior part of the septum
  • vomer -is thin and flat, and forms the posterior and inferior septum
  • septal cartilage -joins with the bony septum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 7.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 899, 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 12.
29
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Case 1.28
Case 1.28
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.28
  1. Right infraorbital foramen
  2. Left lamina papyracea
  3. Lateral wall of right maxillary sinus
  4. Right frontal sinus
  5. Left maxillary sinus
Radiograph of the orbits.
The maxillary sinuses, or antra, are the largest paranasal sinuses. They are pyramidal in shape and are situated in the bodies of the maxillae.
  • The zygomatic bone forms the apex
  • The lateral wall of the nasal cavity forms the base/medial wall of maxillary sinus. This is continued superiorly as a bony projection called the uncinate process
  • The floor of the orbit forms the roof
  • The alveolar part of the maxilla forms the floor. There are often elevations on the floor of the maxillary sinus formed from the roots of the maxillary teeth below.
The superior alveolar branches of the maxillary artery supply the majority of the maxillary sinus, with the greater palatine artery supplying the floor. The anterior, middle and posterior superior alveolar nerves-branches of the maxillary nerve-innervate the maxillary sinus.
The infraorbital foramen transmits the terminal branch of the maxillary (cranial nerve V2): the infraorbital nerve. This supplies the skin of the cheek, lower eye lid, lateral side of nose, inferior septum and upper lip, upper premolars, incisors and canines, and the mucosa of the upper lip and maxillary sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 6.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 825.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 15.
30
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Case 1.29
Case 1.29
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.29
  1. Right foramen rotundum
  2. Left superior orbital fissure
  3. Right greater wing of sphenoid
  4. Right body of sphenoid
  5. Left ethmoidal air cells
Detail of occipitofrontal projection
The sphenoid bone forms part of the middle cranial fossa and contributes to the bony orbit. It consists of a body, greater and lesser wings and pterygoid processes. The wings spread laterally, and the pterygoid processes (lateral and medial pterygoid plates) project inferiorly. The body contains the sphenoid sinuses.
The superior orbital fissure is adjacent to the optic foramen medially. It is a slit between the greater and lesser wings of sphenoid. It transmits V1, III, IV, and VI cranial nerves, superior ophthalmic veins, and a branch of the middle meningeal artery. The ophthalmic artery may communicate with the middle meningeal, therefore forming an anastomotic connection between the internal and external carotid systems.
The foramen rotundum is often visible on facial plain films. It is in the greater wing of sphenoid, posterior to the superior orbital fissure. It travels from the middle cranial fossa to the pterygopalatine fossa and transmits the maxillary (V2) nerve (Figure 1.7).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 2.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 5.
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Figure 1.7: The structures of the superior orbital fissure.
31
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Case 1.30
Case 1.30
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.30
  1. Parotid (Stensen's) duct
  2. Epiglottis
  3. Secondary ductules
  4. Hyoid
  5. Body of C4 vertebra
Parotid sialogram.
In this investigation, the parotid duct is cannulated and radio-opaque contrast injected to outline the ductal system. The parotid is the largest of the three salivary glands. It is irregularly shaped as it occupies the space between the ramus of the mandible and the styloid process of the temporal bone. There is a large superficial part and a smaller deeper part, which are continuous around the ramus of the mandible via the isthmus.
The parotid (Stenson's) duct arches over the masseter muscle before turning medially to pierce the buccinator muscle where it drains into the mouth opposite the second upper molar tooth.
The serous secretions have digestive functions and wash particles of food into the oral cavity. The gland is supplied by branches from the external carotid (which travels through the isthmus) and superficial temporal arteries, and is drained by the retromandibular veins. The facial nerve exits the stylomastoid foramen, runs through the deep parotid and into the superficial parotid where it lies superficial to the external carotid. Here it divides into its five terminal branches.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 35.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 926.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 22.
32
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Case 1.31
Case 1.31
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.31
  1. Right superior canaliculus
  2. Right inferior canaliculus
  3. Right lacrimal sac
  4. Right nasolacrimal duct
  5. Right mastoid air cells
A macrodacryocystogram.
The canaliculi are injected with radio-opaque contrast media to outline the drainage and ducts of the lacrimal apparatus.
The lacrimal gland lies in the superolateral aspect of the orbit in its own fossa. It lies lateral to levator palpebrae superioris which grooves it, dividing it into superior and inferior parts.
The gland secretes tears, which collect in the lacrimal lake at the medial angle of the eye. The tears drain through lacrimal puncta, and into superior and inferior lacrimal canaliculi. The canaliculi drain into the lacrimal sac, and from here into the nasolacrimal duct, which runs in a bony canal to the inferior meatus of the nasal cavity. The valve of Hasner is a mucosal fold at the distal end which prevents reflux into the duct (Figure 1.8).
zoom view
Figure 1.8: The lacrimal apparatus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 23.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 892.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
33
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Case 1.32
Case 1.32
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.32
  1. Incisive canal
  2. Alveolar rim
  3. Right ramus of mandible
  4. Left medial pterygoid muscle
  5. Left masseter muscle
Axial CT of facial bones.
The incisive canals transmit the descending palatine artery and the nasopalatine nerve.
The lateral pterygoid muscle originates from the more lateral aspect of the lateral pterygoid plate. It inserts onto the neck of the mandible and disc of the temporomandibular joint where its main action is to protrude the jaw forward.
The medial pterygoid muscle originates from the more medial aspect of the lateral pterygoid plate to insert onto the ramus of the mandible. Its main action is to elevate the mandible.
The masseter muscle originates the zygomatic process of the maxilla and the zygomatic arch to insert onto the coronoid process and ramus of mandible. Its action is to elevate the mandible and occlude the teeth for chewing and biting (Table 1.1). Gravity also has a role in the depression (i.e. opening) of the mandible and protrusion occurs as a direct consequence of the opening of the mandible.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 8.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 919.
34
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Case 1.33
Case 1.33
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.33
  1. Vomer
  2. Right infratemporal fossa
  3. Left medial pterygoid plate
  4. Right styloid process
  5. Right lateral pterygoid muscle
Axial CT of nares.
The infratemporal fossa is a space posterior to the maxilla, deep to the ramus of the mandible, and deep and inferior to the zygomatic arch. It contains the lateral and medial pterygoid muscles, the inferior part of the temporal muscle, the maxillary artery and the pterygoid venous plexus. It contains many nerves: mandibular, inferior alveolar, lingual, buccal and chorda tympani, as well as the otic ganglion.
The temporal styloid process is a projection from the inferior aspect of the temporal bone. It serves as an anchor point for many of the muscles of the tongue and larynx.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 8.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 919.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 34.
35
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Case 1.34
Case 1.34
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.34
  1. Ostium of left maxillary antrum
  2. Right pterygopalatine fossa
  3. Left sphenopalatine foramen
  4. Right nasolacrimal duct
  5. Right middle turbinate (concha)
Axial CT of base of skull.
The maxillary antrum drains into the middle meatus of the nasal cavity via the maxillary ostium. The nasolacrimal duct conveys tears from the lacrimal apparatus into the inferior meatus of the nasal cavity.
The middle cranial fossa communicates with the pterygopalatine fossa via the foramen rotundum, which opens into it superiorly. The pterygopalatine fossa contains the V2 cranial nerve which enters the orbit through the inferior orbital fissure. It also contains the maxillary artery, the maxillary nerve, the nerve of the pterygoid canal, and the pterygopalatine ganglion.
The sphenopalatine foramen is a communication between the pterygopalatine fossa and the nasal cavity through the perpendicular plate of the palatine bone.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 9.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 35.
36
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Case 1.35
Case 1.35
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.35
  1. Nasal bone
  2. Perpendicular plate of ethmoid bone
  3. Left superior orbital fissure
  4. Right posterior ethmoid air cell
  5. Right medial rectus
Axial CT at level of ethmoid sinus.
The perpendicular plate of the ethmoid bone descends down from the cribriform plate to form the superior part of the bony nasal septum. Above the cribriform plate, it continues as the crista galli.
The ethmoid air cells sit between the lateral walls of the nasal cavity and the medial walls of the orbits. Haller cells are infraorbital extensions of ethmoid air cells. Agger nasi cells are enlarged air cells located anteriorly towards the frontal bones.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 9.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 36.
37
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Case 1.36
Case 1.36
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.36
  1. Crista galli
  2. Left frontozygomatic suture
  3. Right frontal bone
  4. Left lamina papyracea
  5. Cribriform plate
Coronal CT of the paranasal sinuses.
The cribriform plate of the ethmoid is ‘sieve-like’ to allow the olfactory nerves to access the nasal cavity from the olfactory bulbs of the brain. The crista galli is the superior continuation of the perpendicular plate of ethmoid above the cribriform plate.
The frontozygomatic suture is the suture between the frontal and zygomatic bones.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 868.
38
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Case 1.37
Case 1.37
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.37
  1. Right maxillary sinus
  2. Hard palate
  3. Ethmoid air cell
  4. Left middle turbinate (concha)
  5. Left inferior turbinate (concha)
Coronal CT of the paranasal sinuses.
The superior, middle and inferior nasal turbinates (conchae) divide the nasal cavity into four passages:
  • sphenoethmoidal recess into which the sphenoidal sinus drains
  • superior meatus into which the posterior ethmoidal air cells drain
  • middle meatus, where the frontal sinus drains into the anterior opening; the anterior ethmoid air cells and maxillary sinus drain into the middle meatus at the hiatus semilunaris, below the ethmoid bulla
  • inferior meatus into which the nasolacrimal duct drains tears from the lacrimal sac.
The greater palatine, superior labial branch of the facial and ethmoidal branches of the ophthalmic artery supply the nasal cavity. Little's area is a vascular area of mucosa prone to epistaxis in the anterior and inferior septum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 825.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
39
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Case 1.38
Case 1.38
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.38
  1. Left anterior clinoid process
  2. Planum sphenoidale
  3. Right infratemporal fossa
  4. Left greater wing of sphenoid
  5. Right sphenoidal sinus
Coronal CT at the level of the sphenoid sinus.
The clinoid processes are the bony prominences surrounding the sella turcica. The planum sphenoidale forms the roof of the sphenoid sinus.
The sphenoid sinuses are in the body of the sphenoid and are separated by a bony septum. They may extend into the wings of the sphenoid. The sella turcica and optic chiasm are superior. The cavernous sinus runs adjacent to the lateral walls of the sphenoid sinuses; the roof of the nasopharynx is formed by its floor.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 823.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
40
zoom view
Case 1.39
Case 1.39
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.39
  1. Right internal jugular vein
  2. Right sternomastoid
  3. Right strap muscle
  4. Thyroid isthmus
  5. Left lobe of thyroid
Transverse ultrasound section of the thyroid gland.
The thyroid gland is derived from the first and second pharyngeal pouches and lies deep to the sternohyoid and sternothyroid muscles. The central isthmus lies anterior to the trachea and joins the two lateral lobes. On ultrasound the strap muscles and sternomastoid muscle are usually visible anteriorly, along with the common carotid artery and internal jugular vein running adjacent to it in the carotid sheath (Figure 1.9).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 29.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 1040.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 42.
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Figure 1.9: The thyroid and its associated structures.
41
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Case 1.40
Case 1.40
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.40
  1. External carotid arteries
  2. Maxillary artery
  3. Infraorbital artery
  4. Occipital artery
  5. Superficial temporal arteries
External carotid angiogram.
The common carotids bifurcate into the internal and external carotids at the level of C4. The internal carotids have no branches in the neck. The external carotid arteries supply much of the face and neck. They travel posterior and superiorly in the neck, through the substance of the parotid gland, before terminating into the maxillary and superficial temporal arteries. The other branches are the ascending pharyngeal, superior thyroid, lingual, facial, occipital and posterior auricular arteries (Figure 1.10).
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Figure 1.10: The external carotid artery and its branches.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 33.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 855.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 44.
42
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Case 1.41
Case 1.41
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.41
  1. Odontoid peg
  2. Right inferior facet of atlas
  3. Left occipital condyle
  4. Left petro-occipital suture
  5. Pinna of right ear
Coronal CT section of the bones of the neck.
The cervical vertebrae have the foramen transversarium which transmit the vertebral arteries. The C1 vertebral body, the atlas (Atlas, in Greek mythology, supported the weight of the earth on his shoulders) supports the weight of the skull. The occipital condyles of the foramen magnum rest on the superior articular facets of C1 to transmit the weight of the skull to the vertebral column. The atlas has anterior and posterior arches, and not a spinous process or body. The body is fused with that of the axis to become the odontoid process.
The C2 vertebral body, the axis, has two large superior articular facets which allow the atlas to rotate on it. The dens, or odontoid process, projects superiorly from the body, and acts as the pivot around which the axis rotates.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 440.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 91-92.
43
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Case 1.42
Case 1.42
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.42
  1. Left masseter
  2. Left medial pterygoid
  3. Right parotid gland
  4. Right semispinalis capitus
  5. Left sternocleidomastoid
Axial CT of soft tissues of the neck.
Sternocleidomastoid has two heads originating from the mastoid process of the temporal bone and the superior nuchal line of the occipital bone. The sternal head attaches to the manubriosternum, and the clavicular head attaches to the medial third of the clavicle. Acting together, they flex the neck. Acting individually, they rotate the head and neck. The two heads of the sternocleidomastoid divide the neck into the anterior and posterior triangles (Table 1.2).
The transversospinal muscle group is one of the deep or intrinsic layers of back muscles, along with splenius and erector spinae muscles. Semispinalis is the most superficial of the transversospinal group, with the semispinalis capitis having the most superior attachment.
Table 1.2   The muscles of the neck
Muscle type
Muscles
Lateral
• Platysma
• Sternocleidomastoid
• Trapezius
Suprahyoid
• Mylohyoid
• Geniohyoid
• Stylohyoid
• Digastric
Infrahyoid
• Sternohyoid
• Omohyoid
• Sternothyroid
• Thyrohyoid
It travels from the occipital bone to the cervical and transverse processes. It aids in maintaining posture and controlling movements of the vertebral column.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 24.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 471, 1007.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 22.
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Case 1.43
Case 1.43
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.43
  1. Right malleus
  2. Right incus
  3. Right vestibule
  4. Right internal auditory meatus
  5. Left mastoid air cells
High-resolution axial CT of the temporal bone.
The ear has two functions: hearing and equilibrium. The function of the external ear is to collect and conduct sound to the tympanic membrane.
The tympanic membrane is the border between the external and middle ear. The middle ear is a cavity in the petrous temporal bone, consisting of the tympanic cavity just internal to the tympanic membrane, and an epitympanic recess/attic just superior to the membrane. The tympanic membrane is attached to the external auditory canal by a small spur of bone called the scutum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
45
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Case 1.44
Case 1.44
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.44
  1. Left Eustachian tube
  2. Left oval window
  3. Right aditus ad antrum
  4. Right epitympanic recess/attic
  5. Right petrous temporal bone
High-resolution axial CT of the temporal bone.
The tegmen tympani is a thin plate of bone forming the roof of the tympanic cavity and separating it from the middle cranial fossa and temporal lobe. A narrow posterior opening in the attic, the aditus to the mastoid antrum, communicates with the mastoid air cells, therefore acting as a route for the spread of infection.
The floor of the cavity is a thin plate of bone separating it from the bulb of the jugular vein, and is continuous with the Eustachian tube, which runs into the lateral wall of the nasopharynx.
The medial wall is the lateral wall of the inner ear. There are prominences from the lateral semicircular canal (the arcuate eminence), and the initial/basal turn of the cochlea (the promontory).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
46
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Case 1.45
Case 1.45
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.45
  1. Right cochlea
  2. Left malleus
  3. Left incus
  4. Right carotid canal
  5. Left hypotympanum
High-resolution CT (coronal reformat) of the temporal bone.
There are three ossicles which transmit vibrations from the tympanic membrane to the oval window. The malleus is attached to the tympanic membrane, and articulates with the incus at the incudomallear joint. The incus articulates with the stapes, which is attached to the oval window. The round window is inferior and allows pressure equalisation within the vestibule.
Tensor tympani, supplied by the mandibular nerve, inserts onto the malleus to tense the tympanic membrane in the presence of loud sounds.
The inner ear lies medial to the middle ear (Figure 1.11). The bony labyrinth consists of a vestibule, which is a communication between the anterior cochlea, and the posterior semicircular canals. The vestibular duct opens into the posterior fossa.
The cochlea is spiral, consisting of 2.5-2.75 turns, and is the hearing apparatus. The cochlear duct passes parallel to the internal auditory meatus to open in the posterior fossa.
The three semicircular canals (anterior, posterior and lateral) are the balance apparatus.
The internal auditory meatus transmits the facial (anteriorly) and vestibulocochlear nerves (posteriorly) from the posterior fossa.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
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Figure 1.11: The inner ear.
47
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Case 1.46
Case 1.46
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.46
  1. Left lobe of the thyroid
  2. Right internal jugular vein
  3. Oesophagus
  4. Prevertebral muscles
  5. Right sternocleidomastoid
Soft tissue axial CT through the neck at the level of the thyroid.
The thyroid is relatively high attenuating on CT due to its high iodine content. The sternocleidomastoid is seen as a large muscular structure anteriorly. The internal jugular vein is posterior to the thyroid, and wider and more irregular than the more medial common carotid artery. The oesophagus is usually collapsed behind the trachea. The prevertebral muscles lie in the floor of the anterior and posterior triangles of the neck. They lie deep to the prevertebral fascia, and anterior to the vertebral bodies. They can be split into anterior and lateral groups (Table 1.3).
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 1005.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 42-43.
Table 1.3   The muscles of the neck
Muscle type
Muscles
Anterior
• Longus colli
• Longus capitis
• Rectus capitis
• Rectus capitis lateralis
Lateral
• Splenius capitis
• Levator scapulae
• Posterior scalene
• Middle scalene
• Anterior scalene
48
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Case 1.47
Case 1.47
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.47
  1. Right sternocleidomastoid muscle
  2. Left ramus of the mandible
  3. Left inferior oblique muscle
  4. Right splenius capitis
  5. Left semispinalis
Axial T1-weighted MRI at the level of the pharynx.
The orientation of the deep muscles of the neck is complex and best described diagrammatically (Figure 1.12).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 26.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 475.
49
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Case 1.48
Case 1.48
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.48
  1. Uvula
  2. Right medial pterygoid
  3. Left lateral pterygoid
  4. Right submandibular gland
  5. Palatal constrictor muscles
Coronal MRI of the neck.
The uvula is a soft tissue projection from the middle of the soft palate. It aids in articulation of speech, particularly in guttural, uvular consonant and clicking sounds not found in English. The palatal constrictor muscles (palatoglossus and palatopharyngeus) run from the base of the uvula to the tongue and pharynx. They form the anterior and posterior fauces, between which the palatine tonsils sit.
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Figure 1.12: The deep muscles of the neck.
The submandibular gland sits in the submandibular or digastric triangle, which is a space between the inferior border of the mandible and the anterior and posterior bellies of the digastric muscle. The submandibular (Wharton's) duct opens in the floor of the mouth adjacent to the frenulum of the tongue.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 935, 1032.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 17, 41.
50
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Case 1.49
Case 1.49
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.49
  1. Sphenoid sinus
  2. Intrinsic muscle of tongue
  3. Soft palate
  4. Hard palate
  5. Mandible
Midline sagittal T2-weighted MRI of the head and neck.
The nasopharynx is the space between the posterior choanae and the soft palate. It communicates with the oropharynx and the nasal cavity.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 940.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 33.
51
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Case 1.50
Case 1.50
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.50
  1. Nasopharynx
  2. Genioglossus
  3. Epiglottis
  4. Intrinsic muscle
  5. Mylohyoid
Midline sagittal MRI of the head and neck.
The muscles of the tongue work synergistically in order to perform movement. The tongue is formed from two groups of muscles which are split down the middle by the fibrous lingual septum. Extrinsic muscles alter the position of the tongue; they originate outside the tongue and attach to it. They are the:
  • genioglossus
  • hyoglossus
  • styloglossus
  • palatoglossus
Intrinsic muscles alter the shape of the tongue; they are confined to the tongue. The tongue is also supported by the muscles of the floor of the mouth (Figures 1.13 and 1.14):
  • mylohyoid forms the floor of the mouth. A muscular sling from the mylohyoid line on the inner aspect of the mandible to the hyoid bone
    zoom view
    Figure 1.13: Coronal anatomy of the tongue and floor of mouth.
    zoom view
    Figure 1.14: Sagittal anatomy of the tongue and pharynx.
  • geniohyoid, superior to mylohyoid, reinforces the floor of the mouth
  • digastricus has two bellies. The anterior runs from the mastoid process to the hyoid bone. The posterior from the anterior mandible to the hyoid bone
  • stylohyoid runs parallel and lateral to the poster digastric, from the styloid process to the hyoid bone.
The epiglottis is attached to the posterior aspect of the thyroid cartilage and protects the larynx by directing swallowed matter laterally into the piriform fossa.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 940.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 33.
52
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Case 1.51
Case 1.51
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.51
  1. Posterior pituitary
  2. Anterior pituitary
  3. Optic tract
  4. Suprasellar cistern
  5. Mammillary body
Coronal T1-weighted MRI through the pituitary fossa.
The optic chiasm can be seen just superior to the pituitary gland.
The suprasellar cistern is the subarachnoid cistern just superior to the pituitary, between the third ventricle and the diaphragma sellae. It is continuous with the sylvian cistern laterally and the interpeduncular cistern posteriorly. Part of the anterior circle of Willis and optic chiasm sit in the suprasellar cistern.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 54.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 887.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 66.
53
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Case 1.52
Case 1.52
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.52
  1. Right anterior cerebral artery
  2. Pituitary gland
  3. Third ventricle
  4. Optic chiasm
  5. Pituitary stalk
Sagittal MRI through the pituitary fossa.
The pituitary gland sits in the pituitary fossa of the sella turcica. It is connected to cell bodies of the hypothalamus by a stalk or infundibulum, which arises from the tuber cinereum in the floor of the third ventricle (Figures 1.15 and 1.16).
The posterior lobe produces the hormones oxytocin and vasopressin, and their presence gives a high signal on T1-weighted MRI. They are released in response to nervous stimulation from the hypothalamus.
The anterior lobe is of lower signal and secretes adrenocorticotropic hormone, thyroid-stimulating hormone, luteinising hormone, follicle-stimulating hormone, growth hormone and prolactin in response to factors carried down from the hypothalamus by the hypophyseal veins.
The third ventricle is the slit-thin midline ventricle which lies between the thalami.
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Figure 1.15: Sagittal anatomy of the third and fourth ventricles.
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Figure 1.16: Coronal anatomy of the cavernous sinus C, carotid artery; SS, sphenoid sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 54.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 887.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 66.
54
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Case 1.53
Case 1.53
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.53
  1. Right infraorbital foramen
  2. Right temporomandibular joint
  3. Right angle of mandible
  4. Odontoid peg
  5. Left zygomatic arch
Plain radiograph of the facial bones in an occipitomental projection.
Each half of the mandible is made up of a horizontal body, and vertical ramus, which meet at the angle of the mandible. The two halves of the mandible meet at the symphysis menti in the midline. The ramus has two bony projections at its superior margin-the coronoid process anteriorly, and the condylar process posteriorly, which articulates with the temporal bone at the temporomandibular joint.
The zygoma articulates with the temporal, frontal, and maxillary bones. These sutures are known as:
  • zygomaticotemporal suture
  • zygomaticofrontal suture
  • zygomaticomaxillary suture
Its anterior end acts to reinforce the orbit at its inferolateral margin. The zygoma can be assessed on an occipitomental projection, or a modified Towne's view (PA with mouth open).
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 11, 16.
55
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Case 1.54
Case 1.54
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.54
  1. Right mandibular condyle
  2. Right foramen spinosum
  3. Right jugular foramen
  4. Left foramen ovale
  5. Clivus
Axial CT of the head.
The foramen spinosum is a small foramen in the skull base. It is found posterolaterally to the foramen rotundum, and contains the middle meningeal artery on its path from the infratemporal fossa towards the middle cranial fossa.
The foramen ovale is a larger foramen, found in the greater wing of sphenoid, posterolateral to the foramen rotundum. It contains the third division of the fifth cranial nerve and the accessory meningeal artery as they pass between the middle cranial fossa and the infratemporal fossa.
At the junction of the occipital and petrous bones, posteriorly is found the jugular foramen. It has a course which runs inferomedially from the posterior cranial fossa, and it has a somewhat irregular, often asymmetrical shape. The jugular foramen can be divided into two compartments by a fibrocartilaginous band-the smaller anteromedial compartment is known as the pars nervosa, and the larger posteromedial compartment, the pars vascularis. The pars nervosa contains the inferior petrosal sinus (which drains into the internal jugular vein) and the 9th cranial nerve. The pars vascularis contains the jugular bulb, as well as the ascending occipital and pharyngeal arteries. The 10th and 11th cranial nerves are also found within the pars vascularis.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 94.
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Case 1.55
Case 1.55
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.55
  1. Frontal bone (outer table of skull vault)
  2. Coronal suture
  3. Tongue
  4. Soft palate
  5. Lambdoid suture
Lateral radiograph of an infant's skull.
The skull vault is made up of an inner and outer table (or diploe), between which is found the diploic space. This space is filled with marrow, and is traversed by the diploic veins.
The frontal bone develops in two halves in children, separated vertically by the metopic suture. This usually fuses by the age of 5, however, in some individuals it does not fuse. A persistent metopic suture is found in approximately 5-10% of the population. The floor of the anterior cranial fossa is largely made up of the orbital plates of the frontal bone, with the cribriform plate located between them.
The coronal suture marks the interface between the frontal and parietal bones. The parietal bones are separated from each other by the sagittal suture, which runs perpendicularly from the coronal suture, until it meets the lambdoid suture posteriorly. The lambdoid sutures run at an oblique angle, separating the parietal and occipital bones. The parietal bone also articulates with the greater wing of sphenoid anteriorly, and inferiorly it meets the temporal bone.
The side of the skull vault below the parietal and frontal bones is formed by the greater wing of sphenoid and the squamous part of the temporal bone. The point at which the sutures between the frontal, parietal, sphenoidal and temporal bones meet is known as the pterion. These sutures are as follows:
  • sphenosquamosal: between the sphenoid and temporal bones
  • sphenofrontal: between the greater wing of sphenoid and frontal bones
  • sphenoparietal: between the greater wing of sphenoid and parietal bones
  • squamosal: between the temporal and parietal bones
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 1-3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 21.
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Case 1.56
Case 1.56
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.56
  1. Right Eustachian tube
  2. Right external acoustic canal
  3. Sphenoid sinus
  4. Left carotid canal
  5. Left internal acoustic canal
Axial CT of the head.
The carotid canal transmits the internal carotid artery on its course through the petrous bone. It is a circular opening, found just anterior to the jugular fossa, separated from it by a bony crest. It is separated from the inner ear, laterally, by the tympanic plate. The internal carotid takes a tortuous course, and the carotid canal has a vertical course at first, before turning at right angles to continue in a horizontal and medial direction, with the artery then entering the foramen lacerum.
The Eustachian or pharyngotympanic tube connects the lower part of the middle ear with the lateral wall of the nasopharynx. It provides a mechanism for equalising pressure across the tympanic membrane. At its proximal end, the Eustachian tube is bony, but as it continues over approximately 3.5 cm, it becomes cartilaginous.
The internal auditory canal transmits the 7th (facial) and 8th (vestibulocochlear) cranial nerves as well as the labyrinthine artery from the posterior fossa. It is approximately 1cm in length, and runs a roughly horizontal course in the coronal plane. At the lateral end of the canal both nerves pass through the lamina cribrosa, after which the facial nerve continues through the facial canal and the vestibulocochlear nerve gives off branches to supply the cochlea and vestibule. The canal itself is divided into four quadrants by the crista falciformis, which runs horizontally, and the vertical crests. The posterior quadrants are occupied by the superior and inferior vestibular branches of the vestibulocochlear nerve. The anterosuperior compartment of the canal is occupied by the facial and intermediate nerves. The anteroinferior compartment is occupied by the cochlear branch of the vestibulocochlear nerve.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 91.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8, 29.
Cunningham DJ, edited by Robinson A. Cunningham's textbook of anatomy. New York: William Wood and Company, 1898: 129.
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Case 1.57
Case 1.57
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.57
  1. Right infratemporal fossa
  2. Nasopharynx
  3. Left anterior clinoid process
  4. Left greater wing of sphenoid
  5. Left lateral pterygoid plate
Coronal CT of the head.
The sphenoid bone is made up of a body (the basisphenoid), greater and lesser wings, as well as the pterygoid plates, which extend inferiorly behind the maxilla. The lesser wing of the sphenoid bone makes up the posterior part of the floor of the anterior cranial fossa, while the greater wing forms the floor of the middle cranial fossa. The posterior border of the lesser wing is demarcated by the sphenoid ridge, while the posterior border of the greater wing is found where it meets the petrous ridge. Below the greater wing of sphenoid is found the infratemporal fossa, into which open the foramen ovale and spinosum.
The sphenoid sinuses are contained within the body of sphenoid. These are paired, usually asymmetric structures.
The infratemporal fossa is found below the floor of the middle cranial fossa, lateral to the nasopharynx and posterior to the maxilla. Behind it is found the styloid process, the carotid artery, jugular vein, and the deep part of the parotid gland. Laterally, this space extends to the zygomatic arch, mandibular ramus and the temporalis muscle. There is no separation between the temporal fossa superiorly and the infratemporal fossa below-they communicate via the space between the zygomatic arch and the skull.
The medial extent of the infratemporal fossa is bounded by the lateral pterygoid plate, and the pterygoid muscles are contained within it. The pterygomaxillary fissure separates the pterygoid plates from the maxilla superiorly.
There is a small medial depression of the pterygomaxillary fissure, called the pterygopalatine fossa, which is found between the pterygoid process and the posterior maxilla. This fossa has several spaces which open into it. Superiorly, it communicates with the orbit via the inferior orbital fissure, and the middle cranial fossa via the foramen rotundum. Through the sphenopalatine foramen, it communicates with the nasal cavity, and through the greater palatine canal, the mouth. Laterally, this space opens out into the infratemporal fossa. From the foramen rotundum, the maxillary division of the 5th cranial nerve crosses this space before passing through the inferior orbital fissure. It also contains the pterygopalatine segment of the maxillary artery.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 35.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 22.
59
zoom view
Case 1.58
Case 1.58
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.58
  1. Right foramen lacerum
  2. Right lambdoid suture
  3. Left petro-occipital fissure
  4. Left carotid canal
  5. Internal occipital protuberance
Axial CT of the head.
The temporal bone is made up of four parts:
  • squamous: forms part of the skull base and the lateral vault
  • petrous: forms part of the skull base and contains the middle and inner ears
  • mastoid: contains mastoid air cells within the mastoid process behind the ear
  • styloid process: inferior projection.
The occipital bone makes up the posterior aspect of the skull vault, and continues anteriorly to form part of the skull base. It contains the foramen magnum, anterior to which it forms the clivus. This portion, anterior to the foramen magnum, is known as the basiocciput, and articulates with the sphenoid bone anteriorly, and the petrous temporal bone laterally. The petro-occipital fissure is found at the base of the petrous temporal bone and the clivus, and is continuous with the jugular foramen posteriorly.
The internal occipital protuberance is a bony prominence on the internal surface of the posterior cranial fossa in the midline, and marks a point of attachment of the tentorium cerebelli.
The foramen lacerum is a jagged bony canal found posteriorly and medial to the foramen ovale, between the petrous apex, the body of sphenoid and the basiocciput. The internal carotid artery traverses the superior part of the foramen lacerum; it contains only small veins and nerves.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 23.
60
zoom view
Case 1.59
Case 1.59
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.59
  1. Crista galli
  2. Right superior orbital fissure
  3. Right greater wing of sphenoid
  4. Left innominate line
  5. Left foramen rotundum
Frontal skull radiograph.
The crista galli is a bony protrusion from the internal surface of the floor of the anterior cranial fossa in the midline. It marks a point of attachment of the falx cerebri, which is a dural septum that runs in the sagittal plane between the two hemispheres.
The superior orbital fissure is triangular in shape, and is found between the greater and lesser wings of the sphenoid bone. The structures which pass through this fissure are:
  • 3rd cranial nerve
  • 4th cranial nerve
  • first division (orbital) of 5th cranial nerve
  • 6th cranial nerve
  • superior orbital vein
  • middle meningeal artery branch vessel
The foramen rotundum passes from Meckel's cave in the middle cranial fossa to the pterygopalatine fossa, with the second division (maxillary) of the 5th cranial nerve running through it. It is circular in shape, and is found posteriorly to the superior orbital fissure in the greater wing of the sphenoid bone. It is best seen on an angled occipitofrontal view (20° caudal), or an occipitomental view.
The innominate line is seen on occipitomental views of the orbits as a straight line running obliquely from the upper outer part of the orbit, inferiorly and medially. It is caused by the beam hitting the curve of the greater wing of sphenoid at a tangent.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 64, 98.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8, 11-13.
61
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Case 1.60
Case 1.60
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.60
  1. Anterior fontanelle
  2. Planum sphenoidale
  3. Sagittal suture
  4. Lambda
  5. Left lesser wing of sphenoid
Frontal skull radiograph from an infant.
The sutures have quite a different appearance in the neonate/infant compared to an adult. They begin as straight lines, with open fontanelles at the points where they meet, and there may be wormian bones visible. In the first few days of life, some overlapping of the bones may be seen. As the skull grows and matures, the sutures begin to fuse, and change from having a straight appearance to an interlocking pattern. This appearance develops in the first year, and by 2 years of age the sutures have a more adult, serrated pattern. The anterior fontanelle forms a diamond shape between the coronal, metopic and sagittal sutures. It usually closes by the age of 18 months, at which point the junction between the coronal and sagittal sutures becomes known as the bregma. The posterior fontanelle forms a triangular shape between the sagittal and lambdoid sutures. It usually closes by 6-8 months, and the junction of these sutures is then known as the lambda.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 1, 10.
62
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Case 1.61
Case 1.61
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.61
  1. Posterior clinoid process
  2. Dorsum sellae
  3. Floor of anterior cranial fossa
  4. Pituitary fossa (sella turcica)
  5. Hard palate
Lateral skull radiograph.
The pituitary fossa, or sella turcica, is found on the superior surface of the body of sphenoid. The posterior part of the pituitary fossa is known as the dorsum sellae-this is continuous with the clivus behind. The posterior clinoid processes form two lateral projections, which extend from the dorsum sellae. Anteriorly is found the tuberculum sellae, which is a bony prominence on the anterior surface of the sella. There are two bony projections from the anterior aspect of the sella, which are called the anterior clinoid processes-these are part of the lesser wing of sphenoid. Anterior to the tuberculum sellae, between the anterior clinoid processes, is a depression which is known as the sulcus chiasmaticus; the optic chiasm lies over it, and the optic canals are found to each side of it.
The planum sphenoidale is a horizontal portion of the lesser wing of sphenoid, anterior to the sulcus chiasmaticus. It articulates with the cribriform plate anteriorly.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 22.
63
zoom view
Case 1.62
Case 1.62
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.62
  1. Right coronoid process of mandible
  2. Right pterygoid fossa
  3. Right styloid process
  4. Left nasolacrimal duct
  5. Left lateral pterygoid muscle
Axial CT of the head.
The lacrimal gland produces tears to lubricate the eye. These drain via the lacrimal punctae in the medial margins of each eyelid. They then pass through the superior and inferior lacrimal canaliculae. The canaliculae drain into the lacrimal sac, which is located in a depression in the medial wall of the bony orbit. From here, the lacrimal sac empties into the nasolacrimal duct. This duct passes through a bony canal to the inferior meatus in the nasal cavity.
The styloid process extends inferiorly from the base of the petrous temporal bone. The stylomastoid foramen is found posterior to the styloid process, with the facial nerve passing through it. The styloid process and the styloid muscles separate the nasopharynx anteromedially from the carotid sheath which is found posterolaterally.
Stylopharyngeus contributes to the inner layer of the pharyngeal muscles, and styloglossus runs anteriorly to act as an extrinsic muscle of the tongue. The stylohyoid ligament extends from the styloid process to the superior surface of the hyoid bone, and may sometimes be identified on lateral radiographs if it is calcified.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 20, 28.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 23, 30, 107.
64
Answers
Case 1.1
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.1
  1. Rostrum of the corpus callosum
  2. Genu of the corpus callosum
  3. Body of the fornix
  4. Splenium of the corpus callosum
  5. Mamillary body of the hypothalamus
Midline sagittal MRI of the brain.
The corpus callosum lies in the depths of the great longitudinal fissure (interhemispheric fissure). It is composed of commissural fibres that unite corresponding regions of the two cerebral hemispheres. In this image we can identify the major parts of the corpus callosum. From rostral to caudal these are: rostrum, genu, body and splenium.
The fornix is a C-shaped fascicle of fibres that links the hippocampus with the mamillary body of the hypothalamus. The horizontal bundles of fibres that come together in the midline form the body of the fornix. The upper surface of this structure provides attachments to the septum pellucidum, a membrane that separates the anterior horns of the lateral ventricles.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
Case 1.2
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.2
  1. Anterior pituitary (adenohypophysis)
  2. Infundibulum
  3. Interpeduncular cistern
  4. Body of corpus callosum
  5. Pineal gland
Midline sagittal MRI of the brain.
The pituitary gland is a pea-sized structure that sits in the sella turcica of the sphenoid bone. It consists of the posterior pituitary (neurohypophysis) and the anterior pituitary (adenohypophysis). The posterior pituitary is a neuronal structure and can be considered as an expansion of the distal part of the infundibulum (pituitary stalk). On a T1-weighted MRI such as this one, the posterior pituitary is bright (high signal). This helps to identify it with confidence. The anterior pituitary is larger.
65
The interpeduncular cistern is located at the base of the brain, spanning the space between the temporal lobes. It is deepest between the cerebral peduncles of the midbrain, hence the name. It contains the optic chiasm where the optic nerves partially cross.
The pineal gland (also called pineal body) lies in the midline immediately rostral to the superior colliculi of the midbrain. It is part of the epithalamus which is one of the four main subdivisions of the diencephalon. The hypothalamus is the most ventral part of the diencephalon and lies inferior to the thalamus and ventromedial to the subthalamus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
Case 1.3
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.3
  1. Clivus
  2. Optic chiasm
  3. Cingulate gyrus
  4. Massa intermedia of thalami
  5. Tonsil of cerebellum
Midline sagittal MRI of the brain.
The clivus (Latin for ‘slope’) is a shallow depression behind the dorsum sellae. It forms a sloping process at the junction of the occipital and sphenoid bones. The optic chiasm is where half of the fibres of the optic nerve cross to the other side. A mass in the pituitary or the suprasellar fossa can compress this structure. The cingulate gyrus lies above the corpus callosum. It is considered as part of the limbic system and it is thus separate to the frontal and parietal lobes. The thalamus resembles a small hen's egg. Together with the hypothalamus, it forms the lateral wall of the third ventricle. The cerebellar tonsils are the most antero-inferior part of the cerebellar hemispheres. They lie close to the midline and therefore can be seen in a midline sagittal image.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Case 1.4
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.4
  1. Pons
  2. Ventral midbrain (tegmentum)
  3. Quadrigeminal plate (tectum)
  4. 4th ventricle
  5. Medulla oblongata
    66
Midline sagittal MRI of the brain.
The brainstem connects the cerebral hemispheres with the spinal cord. It consists of three parts: the midbrain, the pons and the medulla.
The midbrain is the most superior part of the brainstem. The quadrigeminal plate is the dorsal part of the midbrain. It is also referred to as tectum (Latin for ‘roof’). It is separated from the ventral midbrain (tegmentum) by the cerebral aqueduct (aqueduct of Sylvius), which connects the 3rd and 4th ventricles.
The pons is the widest part of the brainstem. It has a bulbous anterior part. Its posterior part forms the upper part of the floor of the 4th ventricle. The lower part of the floor of the 4th ventricle is formed by the posterior surface of the medulla.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 57.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 36.
Case 1.5
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.5
  1. Cisterna magna
  2. Pontine cistern
  3. Suprasellar cistern
  4. Interpeduncular cistern
  5. Quadrigeminal cistern
Midline sagittal MRI of the brain.
The subarachnoid space is deep in several places, particularly around the base of the brain. These spaces are referred to as subarachnoid cisterns and are named according to nearby structures. The cistern magna lies below the cerebellar hemispheres and behind the medulla. The pontine cistern lies between the pons and the clivus. The interpeduncular cistern lies between the temporal lobes and is widest between the cerebral peduncles of the midbrain.
The quadrigeminal cistern lies posterior to the quadrigeminal plate, between the splenium of the corpus callosum and the vermis of the cerebellum. The suprasellar cistern lies above the pituitary fossa. It is continuous posteriorly with the quadrigeminal cistern.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 47.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 74.
Case 1.6
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.6
  1. Right central sulcus
  2. Right precentral gyrus
  3. Right superior frontal sulcus
  4. Left postcentral gyrus
  5. Superior sagittal sinus
    67
Axial MRI through the central sulcus.
The central sulcus (or Rolandic fissure) separates the frontal from the parietal lobe in each hemisphere. It runs in the near coronal plane. Anterior to the central sulcus lies the precentral gyrus which contains the primary motor cortex. Posterior to the central sulcus lies the postcentral gyrus or primary somatosensory cortex.
The superior frontal sulcus runs in the sagittal plane and separates the superior and middle frontal gyri. The posterior end of the superior frontal sulcus forms at right angles with the precentral sulcus. Identifying the precentral sulcus allows us to identify the central sulcus as it is the sulcus immediately posterior to it.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 46.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge University Press, 1999: 43.
Case 1.7
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.7
  1. Right lentiform nucleus
  2. Head of the right caudate nucleus
  3. Anterior horn of the right lateral ventricle
  4. Interhemispheric fissure
  5. Anterior limb of the left internal capsule
Axial MRI of the brain at the level of the lateral ventricles.
This axial section and the midline sagittal MRI must be studied in detail. They contain key anatomical structures and are always likely to feature in the exam. These structures should be studied in sagittal and coronal images to begin to form a three dimensional understanding of brain anatomy.
Within the cerebral hemispheres lie a number of nuclear masses collectively known as basal ganglia. The major components are the caudate nucleus, the putamen and the globus pallidus. For anatomical purposes, the putamen and globus pallidus are together called lentiform or lenticular nucleus. The putamen lies lateral to the globus pallidus.
The anterior limb of the internal capsule separates the lentiform nucleus from the head of the caudate nucleus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
Case 1.8
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.8
  1. Interhemispheric fissure
  2. Right insular cortex
  3. Splenium of corpus callosum
  4. Left tapetum
  5. Posterior limb of the internal capsule
    68
Axial MRI of the brain at the level of the lateral ventricles.
The Sylvian fissure (or lateral sulcus) separates the frontal from the temporal lobes.
Lateral to the putamen, there is a thin sheet of grey matter known as the claustrum. It is sandwiched between two layers of white matter: the external capsule medially and the extreme capsule laterally. Lateral to the extreme capsule and in the floor of the lateral sulcus, lies the cortex referred to as the insula (of Reil).
The left and right cerebral hemispheres fill the cranial vault above the tentorium cerebelli. They are connected in the midline by the corpus callosum which lies deep in the interhemispheric fissure (median longitudinal fissure). The corpus callosum is a large mass of commissural fibres. The genu is its most anterior part. Fibres extending laterally from the body of the corpus callosum are called the tapetum. They form part of the roof and lateral wall of the lateral ventricle.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
Case 1.9
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.9
  1. Right thalamus
  2. Posterior limb of the internal capsule (right)
  3. Anterior horn of the right lateral ventricle
  4. Septum pellucidum
  5. Choroid plexus (left)
Axial CT of the brain at the level of the basal ganglia.
This axial image is at the same level as the image in the previous case. It is, however, a different modality. T1-weighted MRIs can show the anatomy very clearly but CTs of the brain may be used in the exam. Make sure that you are comfortable with both modalities.
The windowing in this image has been set to optimise the appearance of brain parenchyma. The cortical and deep grey matter appears brighter than the white matter.
The thalamus is separated from the lentiform nucleus by the posterior limb of the internal capsule.
The septum pellucidum is a thin triangular membrane that separates the anterior horn of the lateral ventricles. Anatomical variants are common in this structure and you should be familiar with them.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 44.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 56.
Case 1.10
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.10
  1. Fourth ventricle
  2. Right flocculus
    69
  3. Right middle cerebellar peduncle
  4. Right cerebellar hemisphere
  5. Left cerebellopontine angle cistern
Axial MRI at the level of the fourth ventricle.
On axial imaging, the lower pons is dominated by the posterolaterally directed middle cerebellar peduncles. Lateral to these structures lie the cerebellopontine angle cisterns which are limited posteriorly by the flocculi, a pair of small cerebellar lobes.
The fourth ventricle has a ‘roof’ dorsally and a ‘floor’ ventrally. The roof is formed by the cerebellum and the floor by the pons and medulla. The lateral walls are formed by the cerebellar peduncles. Study these structures in the midline sagittal images to form a three dimensional understanding.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 42.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 55.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 32.
Case 1.11
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.11
  1. Right cingulate gyrus
  2. Optic chiasm
  3. Left internal carotid artery
  4. Right Sylvian fissure
  5. Sphenoidal sinus
Coronal T1-weighted MRI of the brain.
In this image we see the internal carotid artery in the cavernous sinus. Note that on a T1-weighted MRI, rapidly flowing blood is displayed as black signal voids. The internal carotid artery is a branch of the common carotid artery and receives 70% of its blood flow. It arises approximately at the level of the C3 vertebral body and enters the skull through the carotid canal. This marks the onset of the petrous segment. It passes through the foramen lacerum where the laceral segment begins. It is a short segment and it ends at the petrolingual ligament, where the cavernous segment begins. The cavernous segment ends at the proximal dura ring.
The optic chiasm is where the optic nerves partially cross. It lies anterior to the pituitary stalk and superomedially to the cavernous sinuses. The body of the sphenoid bone contains the sphenoidal sinuses which provide a route for surgical access to the pituitary gland via the nose.
By reviewing the coronal images we can appreciate the sylvian fissure separates the superior surface of the temporal lobe from the anterior surface of the frontal lobe and the anterior surface of the parietal lobe.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 48-49.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 59.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 45.
70
Case 1.12
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.12
  1. Right hippocampus
  2. Fornix
  3. Third ventricle
  4. Pons
  5. Left external acoustic meatus
Coronal T1-weighted MRI of the brain.
The limbic system is composed of functionally related structures which surround the corpus callosum at the medial surface of the cerebral hemispheres. You may be asked to identify parts of the limbic system such as the cingulate, splenial and parahippocampal gyri, the hippocampus, the dentate gyrus and the fornix. It is worth spending some time studying diagrams of the limbic system and reviewing its appearance on coronal and parasagittal MRIs.
The thalami are bodies of grey matter that lie in the lateral walls of the third ventricle. The external acoustic (or auditory) meatus is part of the external ear. It is a tube that runs medially to the tympanic membrane.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 48-49.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 59.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 45.
Case 1.13
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.13
  1. Right internal carotid artery (cervical segment)
  2. Right internal carotid artery (petrous segment)
  3. Right internal carotid artery (cavernous segment)
  4. Right middle cerebral artery
  5. Right anterior cerebral artery
Magnetic resonance angiography-coronal view.
The internal carotid artery arises from the common carotid artery and lies posterolateral to the external carotid artery. No branches arise from the common carotid artery or the cervical segment of the internal carotid artery.
The internal carotid artery enters the skull through the carotid canal. That is where the petrous segment begins. The course here is anteromedial and horizontal as it can be seen in this image. The artery then turns superiorly and enters the cavernous sinus. At this point the cavernous segment begins. Note the siphon shape that the artery assumes in this segment. Emerging from the cavernous sinus the artery divides into its terminal branches: the anterior cerebral artery and the middle cerebral artery.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
71
Case 1.14
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.14
  1. Right anterior cerebral artery
  2. Left vertebral artery
  3. Right middle cerebral artery
  4. Left internal carotid artery
  5. Posterior cerebral artery
Magnetic resonance angiography-axial view.
The circle of Willis lies in the suprasellar cistern. It is formed by links between the internal carotid arteries and the vertebrobasilar system. The single anterior communicating artery links the two anterior cerebral arteries. There are two posterior communicating arteries, one on each side, that link the internal carotid artery with the vertebrobasilar system. The circle of Willis is not circular in shape but rather is star-shaped (Figure 1.1). It is complete in only a minority of individuals so do not be thrown by a missing branch.
zoom view
Figure 1.1: The circle of Willis.
72
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging. Edinburgh: Saunders, 2004: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
Case 1.15
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.15
  1. Basilar artery
  2. Internal carotid artery
  3. Posterior cerebral artery
  4. Posterior communicating artery
  5. Ophthalmic artery
Magnetic resonance angiography-lateral view.
In this image we see the same vessels as in the previous two images but from the side. On lateral images such as this one and on some catheter angiograms, it is not possible to accurately determine laterality. If that is the case, simply name the vessel rather than guessing the side.
The ophthalmic artery is the first branch of the internal carotid artery distal to the cavernous sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
Case 1.16
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.16
  1. Petrous part of the internal carotid artery
  2. Cavernous part of the internal carotid artery
  3. Middle cerebral artery
  4. Anterior cerebral artery (A1 segment)
  5. Pericallosal artery (A3 segment)
Catheter angiogram of the carotid artery.
Catheter angiography is used for diagnosis and treatment of vascular problems in the brain. This is an image from an angiogram of the carotid artery.
The internal carotid artery is the biggest vessel and has a characteristic shape. The different segments of the artery are seen in this image, including the terminal branches of the internal carotid artery: the anterior and middle cerebral arteries. The anterior cerebral artery arises from the internal carotid artery at the anterior perforated substance. It is divided into segments:
  • A1 is the first segment and it extends from the origin to the level of the anterior communicating artery.
  • A2 begins after the anterior communicating artery and continues to the bifurcation of the artery into its terminal branches.73
Two branches are given off in A2:
  • The orbital frontal artery is the first branch after the anterior communicating artery.
  • The frontopolar artery arises distal to the orbital frontal, close to where the artery loops over the genu.
After the artery loops over the genu, it passes posteriorly on the superior surface of the corpus callosum. At this point it bifurcates into the callosal marginal and the pericallosal artery (which forms the A3 segment).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 36-40.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 80-87.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
Case 1.17
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.17
  1. Vertebral artery
  2. Basilar artery
  3. Posterior communicating artery
  4. Posterior cerebral artery
  5. Superior cerebellar artery
Catheter angiogram of the vertebral artery.
The vertebral arteries are the first branches of the subclavian arteries on each side. They ascend the neck within the foramina transversaria. They pass through the foramen magnum to enter the skull. At that point they pierce the dura and enter the subarachnoid space. The left and right vertebral arteries join to form the basilar artery at the level of the pontomedullary junction. The posterior inferior cerebellar arteries (PICA) arise from the vertebral arteries just before they join. The anterior inferior cerebellar arteries (AICA) and the superior cerebellar arteries arise from the basilar artery.
In this image we see the left vertebral artery entering the skull and continuing as the basilar artery after joining with the right vertebral artery. The terminal branches are labelled: the posterior cerebral arteries and the posterior communicating arteries. Just before the basilar artery splits into the terminal branches, it gives off the superior cerebellar artery.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 38.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 85.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 50-57.
Case 1.18
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.18
  1. Superior sagittal sinus
  2. Straight sinus
  3. Confluence of sinuses (torcular herophili)
  4. Transverse sinus
  5. Sigmoid sinus
    74
Magnetic resonance venogram.
The venous drainage of the brain (Figure 1.2) does not follow the arterial supply. The venous sinuses are low pressure veins within folds of dura. The superior sagittal sinus begins anteriorly and runs to the back in the midline to the internal occipital protuberance. Posteriorly the sinus turns to one side (usually the right) and continues as the transverse sinus.
zoom view
Figure 1.2: Venous drainage of the brain-lateral view.
The inferior sagittal sinus runs in the lower free edge of the falx cerebri. Posteriorly it joins the great cerebral vein to become the straight sinus. The straight sinus then runs posteriorly to meet the sagittal sinus at the confluence of sinuses (torcular herophili). The transverse sinuses run on either side to the mastoid bone where they turn inferiorly and become the sigmoid sinuses. The transverse and sigmoid sinuses together are known as the lateral sinus. The sigmoid sinus continues through the jugular foramen as the internal jugular vein.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 39-41.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 87-90.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 57-58.
Case 1.19
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.19
  1. Inferior sagittal sinus
  2. Internal cerebral vein
  3. Basal vein of Rosenthal
  4. Great cerebral vein (of Galen)
    75
  5. Internal jugular vein
Magnetic resonance venogram.
The internal cerebral veins run in the roof of the third ventricle on each side and unite under the splenium of the corpus callosum, to form the great cerebral vein of Galen. This is a short vein that passes posterosuperiorly behind the splenium to drain in the anterior end of the straight sinus where it unites with the inferior sagittal sinus.
The basal veins of Rosenthal begin at the anterior perforated substance by the union of the anterior cerebral vein, the deep middle cerebral vein and the striate veins. The basal veins of Rosenthal pass around the midbrain on each side to join the great cerebral vein of Galen (Figure 1.2).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 39-41.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 87-90.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 57-58.
Case 1.20
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.20
  1. Right superior rectus
  2. Right optic nerve
  3. Left superior oblique
  4. Left medial rectus
  5. Vomer
Coronal soft tissue CT through the orbits.
Six extrinsic ocular muscles insert into the sclera. The four rectus muscles arise from a common tendinous ring (annulus of Zinn) that surrounds the optic canal and part of the superior orbit fissure. They insert onto the globe anterior to the equator and have the following functions:
  • medial rectus rotates the pupil medially
  • lateral rectus rotates the pupil laterally
  • superior rectus rotates the pupil superiorly
  • inferior rectus rotates the pupil inferiorly
The superior oblique arises from the sphenoidal bone superomedial to the optic foramen. It passes through the trochlea to insert onto the upper outer surface posterior to the equator, directing the pupil inferiorly and laterally.
The inferior oblique arises from the orbital floor to insert onto the lower outer part posterior to the equator, directing the pupil laterally and superiorly.
The vomer forms the bony part of the nasal septum and separates the choanae.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 889.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 27.
76
Case 1.21
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.21
  1. Frontal sinus
  2. Hard palate
  3. Anterior arch of atlas
  4. Clivus
  5. Pituitary fossa
Lateral skull radiograph.
The frontal sinuses are often asymmetrical and lie between the inner and outer tables of the frontal bone above the nose and medial orbits. They are lined by mucus secreting epithelium, and drain through the frontonasal duct into the infundibulum, which opens into the semilunar hiatus of the middle meatus.
The palate forms the floor of the nasal cavities and the roof of the mouth. The hard (bony) palate is concave and formed from the palatine processes of the maxillae and the horizontal plates of the palatine bones.
The pituitary fossa is a depression in the sella turcica of the upper surface of the sphenoid bone in which the pituitary gland sits. The sella turcica is surrounded by the anterior and posterior clinoid processes (clinoid meaning ‘bedpost’) like the posts of a four poster bed. The posterior part of the sella turcica is the dorsum sellae, which is continuous with the clivus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 6.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 934, 957.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 4.
Case 1.22
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.22
  1. Sagittal suture
  2. Right lambdoid suture
  3. Right frontal sinus
  4. Left maxillary sinus
  5. Ramus of right mandible
Occipitofrontal skull projection.
The sagittal suture is in the midline between the two parietal bones. The two parietal bones are joined to the occipital bone by the lambdoid suture, which is often visible on an occipitofrontal projection. The frontal bones join the parietal bones at the coronal suture. The bregma is the junction between the coronal and sagittal sutures, and the lambda is the junction between the lambdoid and sagittal sutures (Figure 1.3).
77
zoom view
Figure 1.3: The cranial bones and sutures.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 2-6.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 5.
Case 1.23
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.23
  1. Right temporomandibular fossa
  2. Left mandibular notch
  3. Right angle of mandible
  4. Right coronoid process
  5. Right external acoustic meatus
Radiographs of both temporomandibular joints.
These are closed and open mouth plain radiographs of the temporomandibular joints.
On opening the mouth the mandibular condyle translates anteriorly. The next question explains the temporomandibular joints in more detail.
Case 1.24
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.24
  1. External auditory meatus
  2. Articular disc
  3. Condyle of mandible
  4. Temporal lobe
  5. Lateral pterygoid muscle
MRI of the temporomandibular joint (TMJ).
The TMJ is a synovial joint, of which the articular surfaces are the articular tubercle of the temporal bone, the mandibular fossa, and the condyle of the mandible (Figure 1.4). These articular surfaces are covered in fibrous cartilage.
78
The joint is separated into superior and inferior compartments (both have a separate synovial membrane) by the fibrocartilaginous disc. Translational movements occur in the superior compartment, rotational in the inferior compartment. The condyle of the mandible sits in the fossa at rest, and slides anteriorly on to the articular tubercle when open.
Muscles producing mandibular movements at the temporomandibular joints are given in Table 1.1.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 916.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 7.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 17-18.
zoom view
Figure 1.4: The temporomandibular joint.
Table 1.1   The types of mandibular movement at the temporomandibular joint and the muscles that control each one.
Mandibular movement
Muscles involved
Depression (open mouth)
• Suprahyoid
• Infrahyoid
• Lateral pterygoid
Protrusion
• Lateral pterygoid
• Masseter
• Medial pterygoid
Elevation (close mouth)
• Temporalis
• Masseter
• Medial pterygoid
Retrusion
• Temporalis
• Masseter
Lateral movement
• Retractors of same
• Protruders of opposite
79
Case 1.25
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.25
  1. Right lower second molar
  2. Left upper central incisor
  3. Floor of left maxillary sinus
  4. Left lower canine
  5. Hyoid bone
Orthopantomogram (OPG).
An OPG is a panoramic radiograph of the mandible and maxilla in order to image the dentition. It is acquired by rotating a horizontal arm from ear to ear. This means that the central hyoid bone is projected into both edges of the film.
One must not neglect to learn the teeth. OPGs are common examinations.
Case 1.26
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.26
  1. Upper left lateral incisor
  2. Lower left 2nd premolar
  3. Upper right 1st molar
  4. Lower right 3rd molar (Wisdom tooth)
  5. Lower right canine
Orthopantomogram (OPG).
There are 20 deciduous or milk teeth which usually begin erupting by 6 months of age. The symphysis menti fuses at 2 years of age. The permanent teeth develop in the maxilla and mandible during childhood, and are calcified by 3 years of age.
As the permanent teeth erupt, the roots of the deciduous teeth are resorbed. The medial teeth begin erupting before the lateral teeth, and the lower before the upper. The permanent teeth are present by 12-13 years of age, except the wisdom teeth (third molars) which erupt in early adulthood.
There are 20 deciduous teeth, and 32 permanent teeth. In each quadrant:
  • child: two incisors, one canine, two molars.
  • adult: two incisors, one canine, two premolars, three molars.
Supernumerary teeth can be seen on an OPG, and they characteristically occur lateral to the last tooth in each series.
At the centre of each tooth sits the radiolucent highly vascular pulp tissue, which is surrounded by a layer of dentine. Dentine comprises an organic and calcified structure, arranged in porous tubules, and has a radiographic density similar to compact bone. The exposed intraoral portion of each tooth (the crown) has an outer layer of enamel which comprises calcium hydroxyapatite crystals. This is densely radio-opaque. At the cementoenamel junction, which sits at the level of the alveolar ridge, the tooth is no longer covered with enamel, but with cementum. This cementum provides the surround to the root system.
80
The root and neck of the tooth are surrounded by the radiolucent periodontal membrane. The lamina dura is a dense line of bone which surrounds this and each root, and is continuous with the lamina dura of adjacent teeth (Figures 1.5 and 1.6).
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 19.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 34.
Weber E, Netter FH, Vilensky JA, Carmichael SW. Netter's Concise Radiologic Anatomy. Philadelphia: Saunders/Elsevier, 2009: 46.
zoom view
Figure 1.5: The anatomy of the tooth.
zoom view
Figure 1.6: The distribution of adult teeth.
81
Case 1.27
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.27
  1. Right zygomaticofrontal suture
  2. Frontal process of right zygoma
  3. Left lamina papyracea
  4. Nasal septum
  5. Left zygomatic arch
Occipitofrontal projection of facial bones.
The zygomatic/malar bone forms the prominence of the cheek, and articulates with the frontal, maxillary and temporal bones at the zygomaticofrontal, zygomaticomaxillary and zygomaticotemporal sutures respectively. It forms the boundary of the temporal fossa superiorly and the infratemporal fossa inferiorly.
The medial orbit of the wall is formed mainly from ethmoid bone, with contributions from maxillary, lacrimal and sphenoid bones. The paper thin bone separating the orbit from the ethmoid air cells is the lamina papyracea.
The nasal septum is part bony and part cartilaginous and divides the nasal cavity in two in the sagittal plane. The main contributors are:
  • perpendicular plate of ethmoid -descends from the cribriform plate to form the superior part of the septum
  • vomer -is thin and flat, and forms the posterior and inferior septum
  • septal cartilage -joins with the bony septum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 7.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 899, 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 12.
Case 1.28
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.28
  1. Right infraorbital foramen
  2. Left lamina papyracea
  3. Lateral wall of right maxillary sinus
  4. Right frontal sinus
  5. Left maxillary sinus
Radiograph of the orbits.
The maxillary sinuses, or antra, are the largest paranasal sinuses. They are pyramidal in shape and are situated in the bodies of the maxillae.
  • The zygomatic bone forms the apex
  • The lateral wall of the nasal cavity forms the base/medial wall of maxillary sinus. This is continued superiorly as a bony projection called the uncinate process
  • The floor of the orbit forms the roof
    82
  • The alveolar part of the maxilla forms the floor. There are often elevations on the floor of the maxillary sinus formed from the roots of the maxillary teeth below.
The superior alveolar branches of the maxillary artery supply the majority of the maxillary sinus, with the greater palatine artery supplying the floor. The anterior, middle and posterior superior alveolar nerves-branches of the maxillary nerve-innervate the maxillary sinus.
The infraorbital foramen transmits the terminal branch of the maxillary (cranial nerve V2): the infraorbital nerve. This supplies the skin of the cheek, lower eye lid, lateral side of nose, inferior septum and upper lip, upper premolars, incisors and canines, and the mucosa of the upper lip and maxillary sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 6.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 825.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 15.
Case 1.29
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.29
  1. Right foramen rotundum
  2. Left superior orbital fissure
  3. Right greater wing of sphenoid
  4. Right body of sphenoid
  5. Left ethmoidal air cells
Detail of occipitofrontal projection
The sphenoid bone forms part of the middle cranial fossa and contributes to the bony orbit. It consists of a body, greater and lesser wings and pterygoid processes. The wings spread laterally, and the pterygoid processes (lateral and medial pterygoid plates) project inferiorly. The body contains the sphenoid sinuses.
The superior orbital fissure is adjacent to the optic foramen medially. It is a slit between the greater and lesser wings of sphenoid. It transmits V1, III, IV, and VI cranial nerves, superior ophthalmic veins, and a branch of the middle meningeal artery. The ophthalmic artery may communicate with the middle meningeal, therefore forming an anastomotic connection between the internal and external carotid systems.
The foramen rotundum is often visible on facial plain films. It is in the greater wing of sphenoid, posterior to the superior orbital fissure. It travels from the middle cranial fossa to the pterygopalatine fossa and transmits the maxillary (V2) nerve (Figure 1.7).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 2.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 5.
83
zoom view
Figure 1.7: The structures of the superior orbital fissure.
Case 1.30
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.30
  1. Parotid (Stensen's) duct
  2. Epiglottis
  3. Secondary ductules
  4. Hyoid
  5. Body of C4 vertebra
Parotid sialogram.
In this investigation, the parotid duct is cannulated and radio-opaque contrast injected to outline the ductal system. The parotid is the largest of the three salivary glands. It is irregularly shaped as it occupies the space between the ramus of the mandible and the styloid process of the temporal bone. There is a large superficial part and a smaller deeper part, which are continuous around the ramus of the mandible via the isthmus.
The parotid (Stenson's) duct arches over the masseter muscle before turning medially to pierce the buccinator muscle where it drains into the mouth opposite the second upper molar tooth.
The serous secretions have digestive functions and wash particles of food into the oral cavity. The gland is supplied by branches from the external carotid (which travels through the isthmus) and superficial temporal arteries, and is drained by the retromandibular veins. The facial nerve exits the stylomastoid foramen, runs 84through the deep parotid and into the superficial parotid where it lies superficial to the external carotid. Here it divides into its five terminal branches.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 35.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 926.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 22.
Case 1.31
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.31
  1. Right superior canaliculus
  2. Right inferior canaliculus
  3. Right lacrimal sac
  4. Right nasolacrimal duct
  5. Right mastoid air cells
A macrodacryocystogram.
The canaliculi are injected with radio-opaque contrast media to outline the drainage and ducts of the lacrimal apparatus.
The lacrimal gland lies in the superolateral aspect of the orbit in its own fossa. It lies lateral to levator palpebrae superioris which grooves it, dividing it into superior and inferior parts.
The gland secretes tears, which collect in the lacrimal lake at the medial angle of the eye. The tears drain through lacrimal puncta, and into superior and inferior lacrimal canaliculi. The canaliculi drain into the lacrimal sac, and from here into the nasolacrimal duct, which runs in a bony canal to the inferior meatus of the nasal cavity. The valve of Hasner is a mucosal fold at the distal end which prevents reflux into the duct (Figure 1.8).
zoom view
Figure 1.8: The lacrimal apparatus.
85
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 23.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 892.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
Case 1.32
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.32
  1. Incisive canal
  2. Alveolar rim
  3. Right ramus of mandible
  4. Left medial pterygoid muscle
  5. Left masseter muscle
Axial CT of facial bones.
The incisive canals transmit the descending palatine artery and the nasopalatine nerve.
The lateral pterygoid muscle originates from the more lateral aspect of the lateral pterygoid plate. It inserts onto the neck of the mandible and disc of the temporomandibular joint where its main action is to protrude the jaw forward.
The medial pterygoid muscle originates from the more medial aspect of the lateral pterygoid plate to insert onto the ramus of the mandible. Its main action is to elevate the mandible.
The masseter muscle originates the zygomatic process of the maxilla and the zygomatic arch to insert onto the coronoid process and ramus of mandible. Its action is to elevate the mandible and occlude the teeth for chewing and biting (Table 1.1). Gravity also has a role in the depression (i.e. opening) of the mandible and protrusion occurs as a direct consequence of the opening of the mandible.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 8.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 919.
Case 1.33
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.33
  1. Vomer
  2. Right infratemporal fossa
  3. Left medial pterygoid plate
  4. Right styloid process
  5. Right lateral pterygoid muscle
Axial CT of nares.
The infratemporal fossa is a space posterior to the maxilla, deep to the ramus of the mandible, and deep and inferior to the zygomatic arch. It contains the lateral and 86medial pterygoid muscles, the inferior part of the temporal muscle, the maxillary artery and the pterygoid venous plexus. It contains many nerves: mandibular, inferior alveolar, lingual, buccal and chorda tympani, as well as the otic ganglion.
The temporal styloid process is a projection from the inferior aspect of the temporal bone. It serves as an anchor point for many of the muscles of the tongue and larynx.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 8.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 919.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 34.
Case 1.34
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.34
  1. Ostium of left maxillary antrum
  2. Right pterygopalatine fossa
  3. Left sphenopalatine foramen
  4. Right nasolacrimal duct
  5. Right middle turbinate (concha)
Axial CT of base of skull.
The maxillary antrum drains into the middle meatus of the nasal cavity via the maxillary ostium. The nasolacrimal duct conveys tears from the lacrimal apparatus into the inferior meatus of the nasal cavity.
The middle cranial fossa communicates with the pterygopalatine fossa via the foramen rotundum, which opens into it superiorly. The pterygopalatine fossa contains the V2 cranial nerve which enters the orbit through the inferior orbital fissure. It also contains the maxillary artery, the maxillary nerve, the nerve of the pterygoid canal, and the pterygopalatine ganglion.
The sphenopalatine foramen is a communication between the pterygopalatine fossa and the nasal cavity through the perpendicular plate of the palatine bone.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 9.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 35.
Case 1.35
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.35
  1. Nasal bone
  2. Perpendicular plate of ethmoid bone
  3. Left superior orbital fissure
  4. Right posterior ethmoid air cell
  5. Right medial rectus
Axial CT at level of ethmoid sinus.
The perpendicular plate of the ethmoid bone descends down from the cribriform plate to form the superior part of the bony nasal septum. Above the cribriform plate, it continues as the crista galli.
87
The ethmoid air cells sit between the lateral walls of the nasal cavity and the medial walls of the orbits. Haller cells are infraorbital extensions of ethmoid air cells. Agger nasi cells are enlarged air cells located anteriorly towards the frontal bones.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 9.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 824.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 36.
Case 1.36
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.36
  1. Crista galli
  2. Left frontozygomatic suture
  3. Right frontal bone
  4. Left lamina papyracea
  5. Cribriform plate
Coronal CT of the paranasal sinuses.
The cribriform plate of the ethmoid is ‘sieve-like’ to allow the olfactory nerves to access the nasal cavity from the olfactory bulbs of the brain. The crista galli is the superior continuation of the perpendicular plate of ethmoid above the cribriform plate.
The frontozygomatic suture is the suture between the frontal and zygomatic bones.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 868.
Case 1.37
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.37
  1. Right maxillary sinus
  2. Hard palate
  3. Ethmoid air cell
  4. Left middle turbinate (concha)
  5. Left inferior turbinate (concha)
Coronal CT of the paranasal sinuses.
The superior, middle and inferior nasal turbinates (conchae) divide the nasal cavity into four passages:
  • sphenoethmoidal recess into which the sphenoidal sinus drains
  • superior meatus into which the posterior ethmoidal air cells drain
  • middle meatus, where the frontal sinus drains into the anterior opening; the anterior ethmoid air cells and maxillary sinus drain into the middle meatus at the hiatus semilunaris, below the ethmoid bulla
    88
  • inferior meatus into which the nasolacrimal duct drains tears from the lacrimal sac.
The greater palatine, superior labial branch of the facial and ethmoidal branches of the ophthalmic artery supply the nasal cavity. Little's area is a vascular area of mucosa prone to epistaxis in the anterior and inferior septum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 825.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
Case 1.38
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.38
  1. Left anterior clinoid process
  2. Planum sphenoidale
  3. Right infratemporal fossa
  4. Left greater wing of sphenoid
  5. Right sphenoidal sinus
Coronal CT at the level of the sphenoid sinus.
The clinoid processes are the bony prominences surrounding the sella turcica. The planum sphenoidale forms the roof of the sphenoid sinus.
The sphenoid sinuses are in the body of the sphenoid and are separated by a bony septum. They may extend into the wings of the sphenoid. The sella turcica and optic chiasm are superior. The cavernous sinus runs adjacent to the lateral walls of the sphenoid sinuses; the roof of the nasopharynx is formed by its floor.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 11.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 823.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28.
Case 1.39
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.39
  1. Right internal jugular vein
  2. Right sternomastoid
  3. Right strap muscle
  4. Thyroid isthmus
  5. Left lobe of thyroid
Transverse ultrasound section of the thyroid gland.
The thyroid gland is derived from the first and second pharyngeal pouches and lies deep to the sternohyoid and sternothyroid muscles. The central isthmus lies anterior to the trachea and joins the two lateral lobes. On ultrasound the strap 89muscles and sternomastoid muscle are usually visible anteriorly, along with the common carotid artery and internal jugular vein running adjacent to it in the carotid sheath (Figure 1.9).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 29.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 1040.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 42.
zoom view
Figure 1.9: The thyroid and its associated structures.
Case 1.40
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.40
  1. External carotid arteries
  2. Maxillary artery
  3. Infraorbital artery
  4. Occipital artery
  5. Superficial temporal arteries
External carotid angiogram.
The common carotids bifurcate into the internal and external carotids at the level of C4. The internal carotids have no branches in the neck. The external carotid arteries supply much of the face and neck. They travel posterior and superiorly in the neck, through the substance of the parotid gland, before terminating into the maxillary 90and superficial temporal arteries. The other branches are the ascending pharyngeal, superior thyroid, lingual, facial, occipital and posterior auricular arteries (Figure 1.10).
zoom view
Figure 1.10: The external carotid artery and its branches.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 33.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 855.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 44.
Case 1.41
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.41
  1. Odontoid peg
  2. Right inferior facet of atlas
  3. Left occipital condyle
  4. Left petro-occipital suture
  5. Pinna of right ear
Coronal CT section of the bones of the neck.
The cervical vertebrae have the foramen transversarium which transmit the vertebral arteries. The C1 vertebral body, the atlas (Atlas, in Greek mythology, supported the weight of the earth on his shoulders) supports the weight of the skull. The occipital condyles of the foramen magnum rest on the superior articular facets of C1 to transmit the weight of the skull to the vertebral column. The atlas has anterior and 91posterior arches, and not a spinous process or body. The body is fused with that of the axis to become the odontoid process.
The C2 vertebral body, the axis, has two large superior articular facets which allow the atlas to rotate on it. The dens, or odontoid process, projects superiorly from the body, and acts as the pivot around which the axis rotates.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 440.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 91-92.
Case 1.42
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.42
  1. Left masseter
  2. Left medial pterygoid
  3. Right parotid gland
  4. Right semispinalis capitus
  5. Left sternocleidomastoid
Axial CT of soft tissues of the neck.
Sternocleidomastoid has two heads originating from the mastoid process of the temporal bone and the superior nuchal line of the occipital bone. The sternal head attaches to the manubriosternum, and the clavicular head attaches to the medial third of the clavicle. Acting together, they flex the neck. Acting individually, they rotate the head and neck. The two heads of the sternocleidomastoid divide the neck into the anterior and posterior triangles (Table 1.2).
The transversospinal muscle group is one of the deep or intrinsic layers of back muscles, along with splenius and erector spinae muscles. Semispinalis is the most superficial of the transversospinal group, with the semispinalis capitis having the most superior attachment.
Table 1.2   The muscles of the neck
Muscle type
Muscles
Lateral
• Platysma
• Sternocleidomastoid
• Trapezius
Suprahyoid
• Mylohyoid
• Geniohyoid
• Stylohyoid
• Digastric
Infrahyoid
• Sternohyoid
• Omohyoid
• Sternothyroid
• Thyrohyoid
92
It travels from the occipital bone to the cervical and transverse processes. It aids in maintaining posture and controlling movements of the vertebral column.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 24.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 471, 1007.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 22.
Case 1.43
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.43
  1. Right malleus
  2. Right incus
  3. Right vestibule
  4. Right internal auditory meatus
  5. Left mastoid air cells
High-resolution axial CT of the temporal bone.
The ear has two functions: hearing and equilibrium. The function of the external ear is to collect and conduct sound to the tympanic membrane.
The tympanic membrane is the border between the external and middle ear. The middle ear is a cavity in the petrous temporal bone, consisting of the tympanic cavity just internal to the tympanic membrane, and an epitympanic recess/attic just superior to the membrane. The tympanic membrane is attached to the external auditory canal by a small spur of bone called the scutum.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
Case 1.44
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.44
  1. Left Eustachian tube
  2. Left oval window
  3. Right aditus ad antrum
  4. Right epitympanic recess/attic
  5. Right petrous temporal bone
High-resolution axial CT of the temporal bone.
The tegmen tympani is a thin plate of bone forming the roof of the tympanic cavity and separating it from the middle cranial fossa and temporal lobe. A narrow posterior opening in the attic, the aditus to the mastoid antrum, communicates with the mastoid air cells, therefore acting as a route for the spread of infection.
93
The floor of the cavity is a thin plate of bone separating it from the bulb of the jugular vein, and is continuous with the Eustachian tube, which runs into the lateral wall of the nasopharynx.
The medial wall is the lateral wall of the inner ear. There are prominences from the lateral semicircular canal (the arcuate eminence), and the initial/basal turn of the cochlea (the promontory).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
Case 1.45
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.45
  1. Right cochlea
  2. Left malleus
  3. Left incus
  4. Right carotid canal
  5. Left hypotympanum
High-resolution CT (coronal reformat) of the temporal bone.
There are three ossicles which transmit vibrations from the tympanic membrane to the oval window. The malleus is attached to the tympanic membrane, and articulates with the incus at the incudomallear joint. The incus articulates with the stapes, which is attached to the oval window. The round window is inferior and allows pressure equalisation within the vestibule.
Tensor tympani, supplied by the mandibular nerve, inserts onto the malleus to tense the tympanic membrane in the presence of loud sounds.
The inner ear lies medial to the middle ear (Figure 1.11). The bony labyrinth consists of a vestibule, which is a communication between the anterior cochlea, and the posterior semicircular canals. The vestibular duct opens into the posterior fossa.
The cochlea is spiral, consisting of 2.5-2.75 turns, and is the hearing apparatus. The cochlear duct passes parallel to the internal auditory meatus to open in the posterior fossa.
The three semicircular canals (anterior, posterior and lateral) are the balance apparatus.
The internal auditory meatus transmits the facial (anteriorly) and vestibulocochlear nerves (posteriorly) from the posterior fossa.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 14.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 972.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 28-32.
94
zoom view
Figure 1.11: The inner ear.
Case 1.46
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.46
  1. Left lobe of the thyroid
  2. Right internal jugular vein
  3. Oesophagus
  4. Prevertebral muscles
  5. Right sternocleidomastoid
Soft tissue axial CT through the neck at the level of the thyroid.
The thyroid is relatively high attenuating on CT due to its high iodine content. The sternocleidomastoid is seen as a large muscular structure anteriorly. The internal jugular vein is posterior to the thyroid, and wider and more irregular than the more medial common carotid artery. The oesophagus is usually collapsed behind the trachea. The prevertebral muscles lie in the floor of the anterior and posterior triangles of the neck. They lie deep to the prevertebral fascia, and anterior to the vertebral bodies. They can be split into anterior and lateral groups (Table 1.3).
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 1005.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 42-43.
95
Table 1.3   The muscles of the neck
Muscle type
Muscles
Anterior
• Longus colli
• Longus capitis
• Rectus capitis
• Rectus capitis lateralis
Lateral
• Splenius capitis
• Levator scapulae
• Posterior scalene
• Middle scalene
• Anterior scalene
Case 1.47
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.47
  1. Right sternocleidomastoid muscle
  2. Left ramus of the mandible
  3. Left inferior oblique muscle
  4. Right splenius capitis
  5. Left semispinalis
Axial T1-weighted MRI at the level of the pharynx.
The orientation of the deep muscles of the neck is complex and best described diagrammatically (Figure 1.12).
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 26.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 475.
Case 1.48
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.48
  1. Uvula
  2. Right medial pterygoid
  3. Left lateral pterygoid
  4. Right submandibular gland
  5. Palatal constrictor muscles
Coronal MRI of the neck.
The uvula is a soft tissue projection from the middle of the soft palate. It aids in articulation of speech, particularly in guttural, uvular consonant and clicking sounds not found in English. The palatal constrictor muscles (palatoglossus and palatopharyngeus) run from the base of the uvula to the tongue and pharynx. They form the anterior and posterior fauces, between which the palatine tonsils sit.96
zoom view
Figure 1.12: The deep muscles of the neck.
The submandibular gland sits in the submandibular or digastric triangle, which is a space between the inferior border of the mandible and the anterior and posterior bellies of the digastric muscle. The submandibular (Wharton's) duct opens in the floor of the mouth adjacent to the frenulum of the tongue.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 935, 1032.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 17, 41.
Case 1.49
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.49
  1. Sphenoid sinus
  2. Intrinsic muscle of tongue
  3. Soft palate
  4. Hard palate
  5. Mandible
Midline sagittal T2-weighted MRI of the head and neck.
The nasopharynx is the space between the posterior choanae and the soft palate. It communicates with the oropharynx and the nasal cavity.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 940.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 33.
97
Case 1.50
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.50
  1. Nasopharynx
  2. Genioglossus
  3. Epiglottis
  4. Intrinsic muscle
  5. Mylohyoid
Midline sagittal MRI of the head and neck.
The muscles of the tongue work synergistically in order to perform movement. The tongue is formed from two groups of muscles which are split down the middle by the fibrous lingual septum. Extrinsic muscles alter the position of the tongue; they originate outside the tongue and attach to it. They are the:
  • genioglossus
  • hyoglossus
  • styloglossus
  • palatoglossus
Intrinsic muscles alter the shape of the tongue; they are confined to the tongue. The tongue is also supported by the muscles of the floor of the mouth (Figures 1.13 and 1.14):
  • mylohyoid forms the floor of the mouth. A muscular sling from the mylohyoid line on the inner aspect of the mandible to the hyoid bone
    zoom view
    Figure 1.13: Coronal anatomy of the tongue and floor of mouth.
    98
    zoom view
    Figure 1.14: Sagittal anatomy of the tongue and pharynx.
  • geniohyoid, superior to mylohyoid, reinforces the floor of the mouth
  • digastricus has two bellies. The anterior runs from the mastoid process to the hyoid bone. The posterior from the anterior mandible to the hyoid bone
  • stylohyoid runs parallel and lateral to the poster digastric, from the styloid process to the hyoid bone.
The epiglottis is attached to the posterior aspect of the thyroid cartilage and protects the larynx by directing swallowed matter laterally into the piriform fossa.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 30-31.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 940.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 33.
99
Case 1.51
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.51
  1. Posterior pituitary
  2. Anterior pituitary
  3. Optic tract
  4. Suprasellar cistern
  5. Mammillary body
Coronal T1-weighted MRI through the pituitary fossa.
The optic chiasm can be seen just superior to the pituitary gland.
The suprasellar cistern is the subarachnoid cistern just superior to the pituitary, between the third ventricle and the diaphragma sellae. It is continuous with the sylvian cistern laterally and the interpeduncular cistern posteriorly. Part of the anterior circle of Willis and optic chiasm sit in the suprasellar cistern.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 54.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 887.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 66.
Case 1.52
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.52
  1. Right anterior cerebral artery
  2. Pituitary gland
  3. Third ventricle
  4. Optic chiasm
  5. Pituitary stalk
Sagittal MRI through the pituitary fossa.
The pituitary gland sits in the pituitary fossa of the sella turcica. It is connected to cell bodies of the hypothalamus by a stalk or infundibulum, which arises from the tuber cinereum in the floor of the third ventricle (Figures 1.15 and 1.16).
The posterior lobe produces the hormones oxytocin and vasopressin, and their presence gives a high signal on T1-weighted MRI. They are released in response to nervous stimulation from the hypothalamus.
The anterior lobe is of lower signal and secretes adrenocorticotropic hormone, thyroid-stimulating hormone, luteinising hormone, follicle-stimulating hormone, growth hormone and prolactin in response to factors carried down from the hypothalamus by the hypophyseal veins.
The third ventricle is the slit-thin midline ventricle which lies between the thalami.
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zoom view
Figure 1.15: Sagittal anatomy of the third and fourth ventricles.
zoom view
Figure 1.16: Coronal anatomy of the cavernous sinus C, carotid artery; SS, sphenoid sinus.
Weir J, Abrahams P. Imaging Atlas of Human Anatomy, 4th edn. Edinburgh: Mosby, 2010: 54.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 6th edn. Philadelphia: Lippincott Williams & Wilkins, 2009: 887.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2010: 66.
Case 1.53
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.53
  1. Right infraorbital foramen
  2. Right temporomandibular joint
  3. Right angle of mandible
  4. Odontoid peg
  5. Left zygomatic arch
Plain radiograph of the facial bones in an occipitomental projection.
Each half of the mandible is made up of a horizontal body, and vertical ramus, which meet at the angle of the mandible. The two halves of the mandible meet at the symphysis menti in the midline. The ramus has two bony projections at 101its superior margin-the coronoid process anteriorly, and the condylar process posteriorly, which articulates with the temporal bone at the temporomandibular joint.
The zygoma articulates with the temporal, frontal, and maxillary bones. These sutures are known as:
  • zygomaticotemporal suture
  • zygomaticofrontal suture
  • zygomaticomaxillary suture
Its anterior end acts to reinforce the orbit at its inferolateral margin. The zygoma can be assessed on an occipitomental projection, or a modified Towne's view (PA with mouth open).
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 11, 16.
Case 1.54
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.54
  1. Right mandibular condyle
  2. Right foramen spinosum
  3. Right jugular foramen
  4. Left foramen ovale
  5. Clivus
Axial CT of the head.
The foramen spinosum is a small foramen in the skull base. It is found posterolaterally to the foramen rotundum, and contains the middle meningeal artery on its path from the infratemporal fossa towards the middle cranial fossa.
The foramen ovale is a larger foramen, found in the greater wing of sphenoid, posterolateral to the foramen rotundum. It contains the third division of the fifth cranial nerve and the accessory meningeal artery as they pass between the middle cranial fossa and the infratemporal fossa.
At the junction of the occipital and petrous bones, posteriorly is found the jugular foramen. It has a course which runs inferomedially from the posterior cranial fossa, and it has a somewhat irregular, often asymmetrical shape. The jugular foramen can be divided into two compartments by a fibrocartilaginous band-the smaller anteromedial compartment is known as the pars nervosa, and the larger posteromedial compartment, the pars vascularis. The pars nervosa contains the inferior petrosal sinus (which drains into the internal jugular vein) and the 9th cranial nerve. The pars vascularis contains the jugular bulb, as well as the ascending occipital and pharyngeal arteries. The 10th and 11th cranial nerves are also found within the pars vascularis.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 94.
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Case 1.55
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.55
  1. Frontal bone (outer table of skull vault)
  2. Coronal suture
  3. Tongue
  4. Soft palate
  5. Lambdoid suture
Lateral radiograph of an infant's skull.
The skull vault is made up of an inner and outer table (or diploe), between which is found the diploic space. This space is filled with marrow, and is traversed by the diploic veins.
The frontal bone develops in two halves in children, separated vertically by the metopic suture. This usually fuses by the age of 5, however, in some individuals it does not fuse. A persistent metopic suture is found in approximately 5-10% of the population. The floor of the anterior cranial fossa is largely made up of the orbital plates of the frontal bone, with the cribriform plate located between them.
The coronal suture marks the interface between the frontal and parietal bones. The parietal bones are separated from each other by the sagittal suture, which runs perpendicularly from the coronal suture, until it meets the lambdoid suture posteriorly. The lambdoid sutures run at an oblique angle, separating the parietal and occipital bones. The parietal bone also articulates with the greater wing of sphenoid anteriorly, and inferiorly it meets the temporal bone.
The side of the skull vault below the parietal and frontal bones is formed by the greater wing of sphenoid and the squamous part of the temporal bone. The point at which the sutures between the frontal, parietal, sphenoidal and temporal bones meet is known as the pterion. These sutures are as follows:
  • sphenosquamosal: between the sphenoid and temporal bones
  • sphenofrontal: between the greater wing of sphenoid and frontal bones
  • sphenoparietal: between the greater wing of sphenoid and parietal bones
  • squamosal: between the temporal and parietal bones
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 1-3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 21.
Case 1.56
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.56
  1. Right Eustachian tube
  2. Right external acoustic canal
  3. Sphenoid sinus
  4. Left carotid canal
  5. Left internal acoustic canal
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Axial CT of the head.
The carotid canal transmits the internal carotid artery on its course through the petrous bone. It is a circular opening, found just anterior to the jugular fossa, separated from it by a bony crest. It is separated from the inner ear, laterally, by the tympanic plate. The internal carotid takes a tortuous course, and the carotid canal has a vertical course at first, before turning at right angles to continue in a horizontal and medial direction, with the artery then entering the foramen lacerum.
The Eustachian or pharyngotympanic tube connects the lower part of the middle ear with the lateral wall of the nasopharynx. It provides a mechanism for equalising pressure across the tympanic membrane. At its proximal end, the Eustachian tube is bony, but as it continues over approximately 3.5 cm, it becomes cartilaginous.
The internal auditory canal transmits the 7th (facial) and 8th (vestibulocochlear) cranial nerves as well as the labyrinthine artery from the posterior fossa. It is approximately 1cm in length, and runs a roughly horizontal course in the coronal plane. At the lateral end of the canal both nerves pass through the lamina cribrosa, after which the facial nerve continues through the facial canal and the vestibulocochlear nerve gives off branches to supply the cochlea and vestibule. The canal itself is divided into four quadrants by the crista falciformis, which runs horizontally, and the vertical crests. The posterior quadrants are occupied by the superior and inferior vestibular branches of the vestibulocochlear nerve. The anterosuperior compartment of the canal is occupied by the facial and intermediate nerves. The anteroinferior compartment is occupied by the cochlear branch of the vestibulocochlear nerve.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 91.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8, 29.
Cunningham DJ, edited by Robinson A. Cunningham's textbook of anatomy. New York: William Wood and Company, 1898: 129.
Case 1.57
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.57
  1. Right infratemporal fossa
  2. Nasopharynx
  3. Left anterior clinoid process
  4. Left greater wing of sphenoid
  5. Left lateral pterygoid plate
Coronal CT of the head.
The sphenoid bone is made up of a body (the basisphenoid), greater and lesser wings, as well as the pterygoid plates, which extend inferiorly behind the maxilla. The lesser wing of the sphenoid bone makes up the posterior part of the floor of the anterior cranial fossa, while the greater wing forms the floor of the middle cranial fossa. The posterior border of the lesser wing is demarcated by the sphenoid ridge, while the posterior border of the greater wing is found where it meets the petrous 104ridge. Below the greater wing of sphenoid is found the infratemporal fossa, into which open the foramen ovale and spinosum.
The sphenoid sinuses are contained within the body of sphenoid. These are paired, usually asymmetric structures.
The infratemporal fossa is found below the floor of the middle cranial fossa, lateral to the nasopharynx and posterior to the maxilla. Behind it is found the styloid process, the carotid artery, jugular vein, and the deep part of the parotid gland. Laterally, this space extends to the zygomatic arch, mandibular ramus and the temporalis muscle. There is no separation between the temporal fossa superiorly and the infratemporal fossa below-they communicate via the space between the zygomatic arch and the skull.
The medial extent of the infratemporal fossa is bounded by the lateral pterygoid plate, and the pterygoid muscles are contained within it. The pterygomaxillary fissure separates the pterygoid plates from the maxilla superiorly.
There is a small medial depression of the pterygomaxillary fissure, called the pterygopalatine fossa, which is found between the pterygoid process and the posterior maxilla. This fossa has several spaces which open into it. Superiorly, it communicates with the orbit via the inferior orbital fissure, and the middle cranial fossa via the foramen rotundum. Through the sphenopalatine foramen, it communicates with the nasal cavity, and through the greater palatine canal, the mouth. Laterally, this space opens out into the infratemporal fossa. From the foramen rotundum, the maxillary division of the 5th cranial nerve crosses this space before passing through the inferior orbital fissure. It also contains the pterygopalatine segment of the maxillary artery.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 35.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 22.
Case 1.58
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.58
  1. Right foramen lacerum
  2. Right lambdoid suture
  3. Left petro-occipital fissure
  4. Left carotid canal
  5. Internal occipital protuberance
Axial CT of the head.
The temporal bone is made up of four parts:
  • squamous: forms part of the skull base and the lateral vault
  • petrous: forms part of the skull base and contains the middle and inner ears
  • mastoid: contains mastoid air cells within the mastoid process behind the ear
  • styloid process: inferior projection.
The occipital bone makes up the posterior aspect of the skull vault, and continues anteriorly to form part of the skull base. It contains the foramen magnum, anterior to 105which it forms the clivus. This portion, anterior to the foramen magnum, is known as the basiocciput, and articulates with the sphenoid bone anteriorly, and the petrous temporal bone laterally. The petro-occipital fissure is found at the base of the petrous temporal bone and the clivus, and is continuous with the jugular foramen posteriorly.
The internal occipital protuberance is a bony prominence on the internal surface of the posterior cranial fossa in the midline, and marks a point of attachment of the tentorium cerebelli.
The foramen lacerum is a jagged bony canal found posteriorly and medial to the foramen ovale, between the petrous apex, the body of sphenoid and the basiocciput. The internal carotid artery traverses the superior part of the foramen lacerum; it contains only small veins and nerves.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 23.
Case 1.59
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.59
  1. Crista galli
  2. Right superior orbital fissure
  3. Right greater wing of sphenoid
  4. Left innominate line
  5. Left foramen rotundum
Frontal skull radiograph.
The crista galli is a bony protrusion from the internal surface of the floor of the anterior cranial fossa in the midline. It marks a point of attachment of the falx cerebri, which is a dural septum that runs in the sagittal plane between the two hemispheres.
The superior orbital fissure is triangular in shape, and is found between the greater and lesser wings of the sphenoid bone. The structures which pass through this fissure are:
  • 3rd cranial nerve
  • 4th cranial nerve
  • first division (orbital) of 5th cranial nerve
  • 6th cranial nerve
  • superior orbital vein
  • middle meningeal artery branch vessel
The foramen rotundum passes from Meckel's cave in the middle cranial fossa to the pterygopalatine fossa, with the second division (maxillary) of the 5th cranial nerve running through it. It is circular in shape, and is found posteriorly to the superior orbital fissure in the greater wing of the sphenoid bone. It is best seen on an angled occipitofrontal view (20° caudal), or an occipitomental view.
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The innominate line is seen on occipitomental views of the orbits as a straight line running obliquely from the upper outer part of the orbit, inferiorly and medially. It is caused by the beam hitting the curve of the greater wing of sphenoid at a tangent.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 64, 98.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 8, 11-13.
Case 1.60
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.60
  1. Anterior fontanelle
  2. Planum sphenoidale
  3. Sagittal suture
  4. Lambda
  5. Left lesser wing of sphenoid
Frontal skull radiograph from an infant.
The sutures have quite a different appearance in the neonate/infant compared to an adult. They begin as straight lines, with open fontanelles at the points where they meet, and there may be wormian bones visible. In the first few days of life, some overlapping of the bones may be seen. As the skull grows and matures, the sutures begin to fuse, and change from having a straight appearance to an interlocking pattern. This appearance develops in the first year, and by 2 years of age the sutures have a more adult, serrated pattern. The anterior fontanelle forms a diamond shape between the coronal, metopic and sagittal sutures. It usually closes by the age of 18 months, at which point the junction between the coronal and sagittal sutures becomes known as the bregma. The posterior fontanelle forms a triangular shape between the sagittal and lambdoid sutures. It usually closes by 6-8 months, and the junction of these sutures is then known as the lambda.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 1, 10.
Case 1.61
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.61
  1. Posterior clinoid process
  2. Dorsum sellae
  3. Floor of anterior cranial fossa
  4. Pituitary fossa (sella turcica)
  5. Hard palate
Lateral skull radiograph.
The pituitary fossa, or sella turcica, is found on the superior surface of the body of sphenoid. The posterior part of the pituitary fossa is known as the dorsum sellae 107-this is continuous with the clivus behind. The posterior clinoid processes form two lateral projections, which extend from the dorsum sellae. Anteriorly is found the tuberculum sellae, which is a bony prominence on the anterior surface of the sella. There are two bony projections from the anterior aspect of the sella, which are called the anterior clinoid processes-these are part of the lesser wing of sphenoid. Anterior to the tuberculum sellae, between the anterior clinoid processes, is a depression which is known as the sulcus chiasmaticus; the optic chiasm lies over it, and the optic canals are found to each side of it.
The planum sphenoidale is a horizontal portion of the lesser wing of sphenoid, anterior to the sulcus chiasmaticus. It articulates with the cribriform plate anteriorly.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 3.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 22.
Case 1.62
QUESTION
WRITE YOUR ANSWER HERE
A
Name the structure labelled A.
B
Name the structure labelled B.
C
Name the structure labelled C.
D
Name the structure labelled D.
E
Name the structure labelled E.
Case 1.62
  1. Right coronoid process of mandible
  2. Right pterygoid fossa
  3. Right styloid process
  4. Left nasolacrimal duct
  5. Left lateral pterygoid muscle
Axial CT of the head.
The lacrimal gland produces tears to lubricate the eye. These drain via the lacrimal punctae in the medial margins of each eyelid. They then pass through the superior and inferior lacrimal canaliculae. The canaliculae drain into the lacrimal sac, which is located in a depression in the medial wall of the bony orbit. From here, the lacrimal sac empties into the nasolacrimal duct. This duct passes through a bony canal to the inferior meatus in the nasal cavity.
The styloid process extends inferiorly from the base of the petrous temporal bone. The stylomastoid foramen is found posterior to the styloid process, with the facial nerve passing through it. The styloid process and the styloid muscles separate the nasopharynx anteromedially from the carotid sheath which is found posterolaterally.
Stylopharyngeus contributes to the inner layer of the pharyngeal muscles, and styloglossus runs anteriorly to act as an extrinsic muscle of the tongue. The stylohyoid ligament extends from the styloid process to the superior surface of the hyoid bone, and may sometimes be identified on lateral radiographs if it is calcified.
Ryan S, McNicholas M, Eustace SJ. Anatomy for Diagnostic Imaging, 3rd edn. Edinburgh: Saunders, 2011: 20, 28.
Butler P, Mitchell AM, Ellis H. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999: 23, 30, 107.
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