ANATOMY

Supraorbital nerve: This nerve branches from the frontal nerve (largest branch of the ophthalmic nerve) and runs along the roof of the orbit, emerging from the supraorbital notch to the forehead. It innervates the frontal sinus, upper eyelid, and anterolateral part of the forehead and scalp.

Supratrochlear nerve: Branching from the frontal nerve, this nerve runs anteriorly and medially along the roof of the orbit to the forehead. It innervates the medial superior eyelid and anteromedial forehead.

Lacrimal nerve: This nerve branches from the ophthalmic nerve and runs through the orbit. It innervates the lacrimal gland and lateral part of the superior eyelid.

Infratrochlear nerve: Branching off the nasocillary nerve and running along the medial wall of the orbit, this nerve innervates the skin just lateral to the nose, the medial-most parts of the eyelids, the lacrimal sac, and the lacrimal caruncle (the red, fleshy part in the medial corner of the eye).

External nasal nerve: This nerve branches from the anterior ethmoidal nerve and runs between the nasal bone and lateral nasal cartilage. It innervates the skin of the nose.

Infraorbital nerve: This nerve comes from the maxillary nerve and runs through the orbital floor, emerging from the infraorbital foramen. 2It innervates the maxillary sinus, maxillary teeth, inferior eyelid, skin of the cheek, lateral nose, nasal septum, and upper lip.

Zygomaticofacial nerve: Branching from the zygomatic nerve and running along the zygomatic bone at the inferiolateral part of the orbit, this nerve exits the zygomaticofacial foramen of the zygomatic bone and innervates skin on the cheek.

Zygomaticotemporal nerve: This nerve branches off the zygomatic nerve. It exits via the zygomaticotemporal foramen of the zygomatic bone and innervates the skin over the temple.

Auriculotemporal nerve: Branching off the mandibular nerve near the middle meningeal artery, this nerve runs posteriorly deep to the mandibular ramus and parotid gland. It innervates the skin in the posterior part of the temporal region, the skin of the auricle of the ear, the external acoustic meateus, and the external surface of the tympanic membrane.

Buccal nerve: This nerve is different from the buccal branch of the facial nerve. It branches from the mandibular nerve, runs between the pterygoid muscle, and emerges near the mandibular ramus. It innervates the skin and mucosa of the cheek and part of the gums.

Mental nerve: This nerve branches from the inferior alveolar nerve and emerges from the mandible through the mental foramen. It innervates the skin of the chin and the inside of the lower lip.

Great auricular nerve: This nerve branches from the anterior rami of the 2nd and 3rd cervical spinal nerves and runs upward across the sternocleidomastoid posterior to the external jugular vein. It innervates the skin over the angle of the mandible, the parotid gland, and the earlobe.

Lesser occipital nerve: Also branching from the anterior rami of the 2nd and 3rd cervical spinal nerves, this nerve runs along the posterior border of the sternocleidomastoid and goes up to the ear. It innervates the scalp behind the ear.

Greater occipital nerve: Branching off the posterior ramus of the 2nd cervical spinal nerve and passing through the trapezius, this nerve innervates the scalp of the occipital area.3

3rd occipital nerve: This nerve branches off the posterior ramus of the 3rd cervical nerve and pierces the trapezius. It innervates the scalp in the occipital and suboccipital areas.

ISO System (Worldwide)

Universal Numbering System (USA)

Palmer notation method (Earliest)4

The uppercase letters A through T are used for primary teeth and the numbers 1 − 32 are used for permanent teeth.

The tooth designated “1” is the maxillary right third molar (“wisdom tooth”) and the count continues along the upper teeth to the left side.

Then the count begins at the mandibular left third molar, designated number 17, and continues along the bottom teeth to the right side.

Each tooth has a unique number or letter, allowing for easier use on keyboards.

Commonly used in the USA

ISO System uses a two-digit numbering system in which the first number represents a tooth's quadrant and the second number represents the number of the tooth from the midline of the face.

For permanent teeth, the upper right teeth begin with the number, “1”. The upper left teeth begin with the number, “2”. The lower left teeth begin with the number, “3”. The lower right teeth begin with the number, “4”.

For primary teeth, the sequence of numbers goes 5, 6, 7, and 8 for the teeth in the upper right, upper left, lower left, and lower right respectively.

When speaking about a certain tooth such as the permanent maxillary central incisor, the notation is pronounced “one, one”.

Beware of mixing up the teeth in written form such as 11, 12, 13, 14, 15, 16, 17, 18 between the Universal and ISO systems.5

Permanent teeth (adult) were numbered 1 to 8, and the child primary dentition (also called deciduous, milk or baby teeth) were depicted with a quadrant grid using Roman numerals I, II, III, IV, V to number the teeth from the midline distally. Palmer changed this to A, B, C, D, E.

The Palmer notation consists of a symbol () designating in which quadrant the tooth is found and a number indicating the position from the midline. Adult teeth are numbered 1 to 8, with primary teeth indicated by a letter A to E.

European system of identifying teeth by use of a number for each permanent tooth and a + or - sign to indicate theposition of each tooth, e.g., 6 + is the upper right first permanent molar.

A system for deciduous teeth analogous to that for the permanent teeth in which a 0 is added before the toothnumber, e.g., 03+ is the upper right deciduous canine.

The cervical oesophagus is supplied by the inferior thyroid artery.

The thoracic oesophagus is supplied by bronchial and oesophageal branches of the thoracic aorta.

Four or five oesophageal branches arise from the anterior surface of the aorta and descend obliquely to the oesophagus, where they form a vascular chain that anastomoses above with the oesophageal branches of the inferior thyroid arteries, and below with ascending branches from the left phrenic and left gastric arteries.

Blood from the oesophagus drains into a submucous plexus and thence into a peri-oesophageal venous plexus from which oesophageal veins aries.

The esophageal veins drain blood from the esophagus to the azygos vein, in the thorax, and to the inferior thyroid vein in the neck.

Those from the thoracic oesophagus drain predominantly into bronchial veins.

Those from the cervical oesophagus drain oesophageal veins at the oesophageal opening in the lesser curvature and then drains into the portal vein.

It also drains, although with less significance, to the hemiazygos vein, posterior intercostal vein and bronchial veins.

In the abdomen, some drain to the left gastric vein.

Left Vitelline Vein regresses

Right Vitelline vein forms the portal vein.

The vitelline veins, (omphalomesenteric veins): Carrying blood from the yolk sac to the sinus venosus

The umbilical veins: Originating in the chorionic villi, carrying oxygenated blood to the embryo

The cardinal veins: Draining the body of the embryo proper

Before entering the sinus venosus, the vitelline veins form a plexus around the duodenum and pass through the septum transversum

The liver cords growing into the septum interrupt the course of the veins, and an extensive vascular network, the hepatic sinusoids, forms.

With reduction of the left sinus horn, blood from the left side of the liver is rechanneled toward the right, resulting in an enlargement of the right vitelline vein (right hepatocardiac channel)

The right hepatocardiac channel forms the hepatocardiac portion of the inferior vena cava.

The proximal part of the left vitelline vein disappears.

The superior mesenteric vein derives from the right vitelline vein

The distal portion of the left vitelline vein also disappears.

The hand shows hyperextension of the metacarpophalangeal joints (MCP) and flexion of the distal and proximal Interphalangeal (IP) joints of the 4th and 5th digits (ring and little finger).

The clawing becomes most obvious when the person is asked to flex the digits from an extended position as the 4th and 5th digits cannot flex due to the injury to the ulnar nerve.

1st, 2nd and 3rd digits will partially flex giving them a ‘claw-like’ appearance, this happens because the thenar muscles (Abductor pollicis brevis, Flexor Pollicis brevis and Opponens pollicis) are innervated by the median nerve as the first two lumbricals of digit 2 and 3 are.

An ulnar claw may follow an ulnar nerve lesion which results in the partial or complete denervation of the ulnar (medial) two lumbricals of the hand. Since the ulnar nerve also supplies the 3rd and 4th lumbricals, which flex the MCP joints (aka the knuckles), their denervation causes these joints to become extended by the now unopposed action of the long finger extensors (namely the extensor digitorum and the extensor digiti minimi). The lumbricals and interossei also extend the IP (interphalangeal) joints of the fingers by insertion into the extensor hood; their paralysis results in weakened extension. The combination of hyperextension at the MCP and flexion at the IP joints gives the hand its claw like appearance.

Dupuytren's contracture is a deformity of the hand due to thickening and fibrosis of the palmar aponeurosis and eventual contracture of the 4th and 5th digits. Presenting as a small hard nodule in the base of the ring finger, it tends to affect the ring and little finger as puckering and adherence of the palmar aponeurosis to the skin. Eventually the MCP and IP joints of the 4th and 5th digits become permanently flexed. This claw appearance can be distinguished from an ulnar claw in that the MCP is flexed in Dupuytren's but hyperextended in ulnar nerve injuries.

A claw hand can result of injuries to the inferior brachial plexus (C8 - T1). The condition may arise from the limb being suddenly pulled upward. For example, Klumpke paralysis can occur from excessive pulling of the infant's forelimb during parturition.

The phrenic nerve is a nerve that originates in the neck (C3-C5) and passes down between the lung and heart to reach the diaphragm. It is important for breathing, as it passes motor information to the diaphragm and receives sensory information from it. There are two phrenic nerves, a left and a right one.

The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves (C3-C5) in humans. Thus, the phrenic nerve receives innervation from parts of both the cervical plexus and the brachial plexus of nerves.

The phrenic nerves contain motor, sensory, and sympathetic nerve fibers. These nerves provide the only motor supply to the diaphragm as well as sensation to the central tendon. In the thorax, each phrenic nerve supplies the mediastinal pleura and pericardium.

Found in the middle mediastinum, both phrenic nerves run from C3, C4, and C5 along the anterior scalene muscle deep to the carotid sheath.

On the left, the phrenic nerve crosses anterior to the first part of the subclavian artery. On the right, it lies on the anterior scalene muscle and crosses anterior to the 2nd part of the subclavian artery.

On both sides, the phrenic nerve runs posterior to the subclavian vein as it enters the thorax where it runs anterior to the root of the lung and between the fibrous pericardium and mediastinal face of the parietal pleura.

The right phrenic nerve passes over the brachiocephalic artery, posterior to the subclavian vein, and then crosses the root of the right lung anteriorly and then leaves the thorax by passing through the vena cava hiatus opening in the diaphragm at the level of T8. The right phrenic nerve passes over the right atrium.

The left phrenic nerve passes over the pericardium of the left ventricle and pierces the diaphragm separately.

Birth defect of the diaphragm.

The most common type of CDH is a Bochdalek hernia; other types include Morgagni hernia, diaphragm eventration and central tendon defects of the diaphragm.

It is most frequently caused by failure of one or both of the pleuroperitoneal membranes to close the pericardioperitoneal canals.

The peritoneal and pleural cavities are continuous with one another along the posterior body wall.

In 85% to 90% of cases, the hernia is on the left side, and intestinal loops. stomach, spleen, and part of the liver may enter the thoracic cavity.

The Bochdalek hernia, also known as a postero-lateral diaphragmatic hernia, is the most common manifestation of CDH, accounting for more than 95% of cases.

In this instance the diaphragm abnormality is characterized by a hole in the postero-lateral corner of the diaphragm which allows passage of the abdominal viscera into the chest cavity.

The majority of Bochdalek hernias (80-85%) occur on the left side of the diaphragm

Rare anterior defect of the diaphragm is variably referred to as Morgagni, retrosternal, or parasternal hernia.

Accounting for approximately 2% of all CDH cases, it is characterized by herniation through the foramina of Morgagni which are located immediately adjacent and posterior to the xiphoid process of the sternum.

The septum transversum (most important component) forms the central tendon and is first seen as a thick mesodermal plate cranial to the pericardial cavity between the base of the thoracic cavity and the stalk of the yolk sac:

Pleuroperitoneal membranes fuse with the dorsal mesentery of the esophagus and with the dorsal part of the septum transversum to complete the partition between the thoracic and abdominopelvic cavities to form the primitive diaphragm. They represent only a small portion of the final adult structure.

The dorsal esophageal mesentery (mesoesophagus) fuses with both A and This mesentery forms the median portion of the diaphragm. The crura of the diaphragm develop from muscle fibers which grow into the esophageal mesentery.

The body wall: During weeks 9 to 12, the pleural cavities enlarge and invade the lateral body walls. Body wall tissue, at this time, splits off medially to form the peripheral parts of the diaphragm outside that formed by the membranes.

Occurs when the artery is formed by the distal portion of the right dorsal aorta and the seventh intersegmental artery.

The right fourth aortic arch and the proximal part of the right dorsal aorta are obliterated.

With shortening of the aorta between the left common carotid and left subclavian arteries, the origin of the abnormal right subclavian artery finally settles just below that of the left subclavian artery.

Left aortic arch with an aberrant right subclavian artery, last great vessel on the aortic arch, is the most common congenital anomaly of the aortic arch occurring in about 0.5% of the general population.

Normally, proximal part of the right subclavian artery arises from the right fourth aortic arch and distal part from the right dorsal aorta present between fourth aortic arch and right seventh intersegmental artery and right seventh intersegmental artery.

The ARSCA develops as a result of the abnormal involution of the right fourth aortic arch, right dorsal aorta present between fourth aortic arch and seventh intersegmental artery and abnormal persistence of right dorsal aorta distal to the right seventh intersegmental artery.

It has been reported that the ARSCA typically travels in a retroesophageal course in 80% of patients, between the trachea and esophagus in 10–15% of patients, and anterior to both structures in 5% of patients.

Aberrant subclavian artery; with regression of the right aortic arch 4 and the right dorsal aorta, the right subclavian artery has an abnormal origin on the left side, just below the left subclavian artery. To supply blood to the right arm, this forces the right subclavian artery to cross the midline behind the trachea and esophagus, which may constrict these organs, although usually with no clinical symptoms.

A double aortic arch; occurs with the development of an abnormal right aortic arch in addition to the left aortic arch, forming a vascular ring around the trachea and esophagus, which usually causes dificutly breathing and swallowing. Occasionally, the entire right dorsal aorta abnormally persists and the left dorsal aorta regresses in which case the right aorta will have to arch across from the esophagus causing difficulty breathing or swallowing.

Right-sided aortic arch

Patent ductus arteriosus

Coarctation of the aorta

The three types of gland are all located beneath the gastric pits within the gastric mucosa–the mucous membrane of the stomach. The gastric mucosa is pitted with innumerable gastric pits which house the gastric glands.

The cardiac glands are found in the cardia of the stomach which is the part nearest to the heart, enclosing the opening where the oesophagus joins to the stomach. Only cardiac glands are found here and they primarily secrete mucus. They are fewer in number than the other gastric glands and are more shallowly positioned in the mucosa. There are two kinds - either simple tubular with short ducts or compound racemose resembling the duodenal Brunner's glands

The fundic glands (or oxyntic glands), are found in the fundus and body of the stomach. They are simple almost straight tubes, two or more of which open into a single duct. Oxyntic means acid-secreting and they secrete hydrochloric acid (HCl) and intrinsic factor.

The pyloric glands are located in the antrum of the pylorus. They secrete gastrin produced by their G cells.19

The chief cells are found in the basal regions of the gland and release a zymogen – pepsinogen, a precursor to pepsin.

The parietal cells (parietal means relating to a wall), are found in the walls of the tubes. The parietal cells secrete hydrochloric acid–the main component of gastric acid. This needs to be readily available for the stomach in a plentiful supply, and so from their positions in the walls their secretory networks of fine channels called canaliculi can project and ingress into all the regions of the gastric-pit lumen. Another important secretion of the parietal cells is intrinsic factor. Intrinsic factor is a glycoprotein essential for the absorption of vitamin B12. The parietal cells also produce and release bicarbonate ions in response to histamine release from the nearby ECLs, and so serve a crucial role in the pH buffering system.

The enterochromaffin-like cells store and release histamine when the acidity of the stomach becomes too high. The release of histamine is stimulated by the secretion ofgastrin from the G cells. Histamine promotes the production and release of bicarbonate ions from the parietal cells to the blood and protons to the stomach lumen. When the stomach pH increases, the ECLs stop releasing histamine.

The G cells are mostly found in pyloric glands in the antrum of the pylorus; some are found in the duodenum and other tissues. The G cells secrete gastrin. The gastric pits of these glands are much deeper than the others and here the gastrin is secreted into the bloodstream not the lumen.

These excitatory afferents arise from the entire cerebral cortex and from the intralaminar nuclei of the thalamus (primarily the centromedian nucleus and parafascicularis nucleus).

The projections from different cortical areas are segregated, such that the frontal lobe projects predominantly to the caudate head and the putamen; the parietal and occipital lobes project to the caudate body; and the temporal lobe projects to the caudate tail.21

The primary motor cortex and the primary somatosensory cortex project mainly to the putamen, whereas the premotor cortex and supplementary motor areas project to the caudate head. Other cortical areas project primarily to the caudate.

Thus, along the C-shaped extent of the caudate nucleus, the caudate cells receive their input from the cortical regions that are close by. The enlarged head of the caudate reflects the large projection from the frontal cortex to the caudate.

In addition, the nucleus accumbens (ventral striatum) receives a large input from limbic cortex.

Lymphoid structures located in the mucosa of the tongue, palate, and pharynx which provide sites where immune surveillance cells (lymphocytes) can encounter foreign antigens enter the body through the mouth or nose.24

Each tonsil consists of an epithelial crypt (invaginated pocket) surrounded by dense clusters of lymph nodules, each with a germinal center where lymphocytes proliferate

The nodules are embedded in a mass of diffuse lymphoid tissue that consists of lymphocytes migrating to and from the germinal centers.

Largest lymphatic organ

Many macrophages; RBC phagocytosed

Capsule of dense irregular connective tissue w/trabeculae dividing pulp incompletely

White pulp with lymphoid nodules

Red plup found between sinusoids has reticular fibers, reticular epithelial cells and macrophages

Reticular cells with cords of cells between sinuses

Cords have macrophages, monocytes, lymphocytes, plasma cells, RBC, granulocytes

Sinuses have irregular lumen, incomplete endothelium and basal lamina

Central arteries with encircling lymphoid tissue

T cells form periarterial lymphatic sheaths (PALS) around small arteries

Nodules are mostly B cells

Reticular epithelial cells & macrophages

Lymph nodes are kidney or oval shaped and range in size from a few millimeters to about 1–2 cm long.

Each lymph node is surrounded by a fibrous capsule, and inside the lymph node the fibrous capsule extends to form trabeculae.

The substance of the lymph node is divided into the outer cortex and the inner medulla. The cortex is continuous around the medulla except at the hilum, where the medulla comes in direct contact with the hilum.

Thin reticular fibers and elastin form a supporting meshwork called a reticular network inside the node.

White blood cells (leukocytes), the most prominent ones being lymphocytes, are tightly packed in the follicles (B cells) and the cortex (T cells).

As part of the reticular network there are follicular dendritic cells in the B cell follicle and fibroblastic reticular cells in the T cell cortex.

MALT- mucosa-associated lymphatic tissue:

MALT protects the digestive, genitourinary and respiratory systems

Peyer's patches: isolated clusters of lymphoid tissue, similar to tonsils

Peyer's patches and the appendix:

Central lymphoid organ

Thin capsule, lobular organization

Each lobule has cortex (greater cell density) with many T lympocytes surrounding lighter medulla

Epithelial reticular cells

Hassal's corpuscles (flattened epithelial reticular cells)

Anterior cerebral artery (left and right)

Anterior communicating artery

Internal carotid artery (left and right)

Posterior cerebral artery (left and right)

Posterior communicating artery (left and right)

Basilar artery

The left and right internal carotid arteries arise from the left and right common carotid arteries.

The posterior communicating artery is given off as a branch of the internal carotid artery just before it divides into its terminal branches - 28the anterior and middle cerebral arteries. The anterior cerebral artery forms the anterolateral portion of the circle of Willis, while the middle cerebral artery does not contribute to the circle.

The right and left posterior cerebral arteries arise from the basilar artery, which is formed by the left and right vertebral arteries. Thevertebral arteries arise from the subclavian arteries.

The anterior communicating artery connects the two anterior cerebral arteries and could be said to arise from either the left or right side.

All arteries involved give off cortical and central branches. The central branches supply the interior of the circle of Willis, more specifically, the Interpeduncular fossa. The cortical branches are named for the area they supply. Since they do not directly affect the circle of Willis, they are not dealt with here.

Sebaceous glands empty their secretory product into the upper parts of the hair follicles. They are therefore found in parts of the skin where hair is present. The hair follicle and its associated sebaceous gland form a pilosebaceous unit.

Sebaceous glands are also found in some of the areas where no hair is present, for example, lips, oral surfaces of the cheeks and external genitalia.

Sebaceous glands are as a rule simple and branched (Remember the nomenclature of glands!). The secretory portion consists of alveoli. Basal 32cells in the outermost layer of the alveolus are flattened. Basal cells are mitotically active. Some of the new cells will replenish the pool of basal cells, while the remaining cells are displaced towards the centre of the alveolus as more cells are generated by the basal cells. The secretory cells will gradullay accumulate lipids and grow in size. Finally their nuclei disintegrate, and the cells rupture. The resulting secretory product of lipids and the constituents of the disintegrating cell is a holocrine secretion.

The lipid secretion of the sebaceous glands has no softening effect on the skin, and it has only very limited antibacterial and antifungoid activity. Its importance in humans is unclear. Clinically the sebaceous glands are important in that they are liable to infections (e.g. with the development of acne).

Sebaceous glands will be present in all types of skin other than thick skin. Their numbers should correlate with the number of hair follicles. If your section does not contain hair follicles you are unlikely to see a good sebaceous gland. Sebaceous glands are usually embedded in the dermis. Although they empty into the hair canal of the hair follicle, this point will only be visible for a few of them because of the thinness of the sections. It should however be possible to follow the fate of the secretory cells. Deep in the sebaceous glands cells are smaller with intact nuclei. Cell size increases with the accumulation of sebum as the cells are gradually displaced towards the opening of the gland into the hair follicle. The nuclei condense, become darker and irregularly shaped.

Apocrine glands a portion of the secreting cell's body is lost during secretion. Apocrine gland is often used to refer to the apocrine sweat glands, however it is thought that apocrine sweat glands may not be true apocrine glands as they may not use the apocrine method of secretion. e.g. mammery gland, sweat gland of arm pit, pubic region, skin around anus, lips, nipples.

Holocrine glands the entire cell disintegrates to secrete its substances (e.g., sebaceous glands)sebaceous, meibomiun & zeis gland.

Merocrine glands cells secrete their substances by exocytosis (e.g., mucous and serous glands). Also called “eccrine”. e.g. max sweat gland of humans, goblet cells, salivary gland, tear gland, intestinal glands.

Serous glands secrete a watery fluid like, often protein-rich product. e.g. sweat gland.

Mucous glands secrete a viscous product, rich in carbohydrates (e.g., glycoproteins).goblet cell.

Sebaceous glands secrete a lipid product. These glands are also known as oil glands. pancreas, gastric gland.

Cricothyroid muscle lengthen and tense the vocal folds.

Posterior cricoarytenoid muscles abduct and externally rotate the arytenoid cartilages, resulting in abducted vocal folds.

Lateral cricoarytenoid muscles adduct and internally rotate the arytenoid cartilages, increase medial compression.

Transverse arytenoid muscle adduct the arytenoid cartilages, resulting in adducted vocal folds.^[2]

Oblique arytenoid muscles narrow the laryngeal inlet by constricting the distance between the arytenoid cartilages.36

Thyroarytenoid muscles - sphincter of vestibule, narrowing the laryngeal inlet, shortening the vocal folds, and lowering voice pitch. The internal thyroarytenoid is the portion of the thyroarytenoid that vibrates to produce sound.

Portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes).

The insulae are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body's homeostasis.

These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience.

The cortical area overlying the insula toward the lateral surface of the brain is the operculum(meaning lid). The opercula are formed from parts of the enclosing frontal, temporal, and parietal lobes.

The anterior part of the insula is subdivided by shallow sulci into three or four short gyri.

The anterior insula receives a direct projection from the basal part of the ventral medial nucleus of the thalamus and a particularly 38large input from the central nucleus of theamygdala. In addition, the anterior insula itself projects to the amygdala.

The posterior part of the insula is formed by a long gyrus.

The posterior insula connects reciprocally with the secondary somatosensory cortex and receives input from spinothalamically activated ventral posterior inferior thalamic nuclei. It has also been shown that this region receives inputs from the ventromedial nucleus (posterior part) of the thalamus that are highly specialized to convey homeostatic information such as pain, temperature, itch, local oxygen status, and sensual touch.

The ‘circular sulcus of insula’ (or sulcus of Reil)is a semi-circular sulcus or fissure that separates the insula from the neighboring gyri of the operculum in the front, above, and behind.