Succinct Concise Anatomy for Dental Students with MCQs Nagesh Khurana, Aafreen Aftab
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Scalp1

 
SCALP
The soft tissue covering the vault of skull is known as scalp.
 
Extent
Anterior
:
Superaciliary arches
Posterior
:
External occipital protuberance and superior nuchal lines.
Lateral
:
Superior temporal line on each side
 
Layers
Consists of five layers:
S
:
Skin
C
:
Connective tissue
A
:
Aponeurosis
L
:
Loose areolar tissue
P
:
Periosteum
 
Skin
Richly supplied with hair, sweat glands and sebaceous glands.
 
Connective Tissue (Superficial Fascia)
  • Blood vessels of scalp lie in this layer.
  • Any injury here results in profuse bleeding as it is richly supplied by blood vessels.
  • It consists of fat bounded with fibrous septa which binds skin to the subjacent aponeurosis.
 
Aponeurosis
  • Formed by the aponeurosis (a fibrous connective tissue that attaches muscle to bone or other tissue) of occipitofrontalis muscle over the bone of skull.
  • Occipitofrontalis originates from two parts/bellies:
    1. Occipital belly
    2. Frontal belly
  • The fibers of both bellies are inserted into a central fibrous layer known as Galea Aponeurotica/Epicranial apponeurosis.
 
Extent
Anterior
:
Root of nose
Posterior
:
External occipital protuberance and highest nuchal lines on either side
Lateral
:
Zygomatic arch
 
Loose Areaolar Tissue
  • It lies below the aponeurotic layer.
  • Responsible for the mobility of scalp.
  • Surgeons mobilize flaps in this plane for reconstructive surgery.
 
Periosteum (Pericranium)
  • Innermost layer which is loosely attached to the surface of bone.
  • Firmly adherent to the suture lines.
 
DANGEROUS LAYER OF THE SCALP
  1. This layer is called the dangerous layer of scalp as it lodges the emissary veins which do not have valves (Fig. 1.1).
  2. Emissary veins connect the extracranial veins with the intracranial venous sinuses to equalize the pressure.
  3. Hence, if there is any infection of scalp, it can travel along the emissary vein into the intracranial dural venous sinuses leading to thrombosis.
2
zoom view
Fig. 1.1: Layers of scalp
 
BlOOD SUPPLY
 
Arterial Supply – By Five Arteries
 
Front of Ear
  1. Supratrochlear
Branch of ophthalmic artery
  1. Supraorbital
  1. Superficial temporal
 
Behind the Ear
  1. Posterior auricular
Branch of external carotid artery
  1. Occipital
 
Venous Supply—Veins Accompany the Arteries
  • Supratrochlear
  • Supraorbital
  • Superficial temporal
  • Posterior auricular
  • Occipital
 
Nerve Supply
 
Sensory
Supplied by eight sensory nerves
 
Front of the Ear
  1. Supratrochlear
Branch of trigeminal nerve
  1. Supraorbital
  1. Zygomaticotemporal
  1. Auriculotemporal
 
Behind the Ear
  1. Great auricular
Arise from cervical plexus
  1. Lesser occipital
  1. Greater occipital
  1. Third occipital
Motor—By two nerves
  1. Temporal
Branch of facial nerve
  1. Posterior auricular
 
Lymphatic Drainage
  1. Preauricular lymph node—Drain anterior part of scalp.
  2. Post–auricular lymph nodes—Drain posterior part of scalp.
  3. Occipital lymph nodes.
 
Applied / Clinical Anatomy
  1. Sebaceous cysts are common as sebaceous glands are abundant in the scalp.
  2. Because of rich blood supply, the avulsed portion need not to be cut away, so it can be repositioned, sutured hence heals well.
  3. The loose areolar tissue layer is the dangerous layer of scalp because emissary veins are lodged in this layer.
  4. Wounds of the scalp bleed profusely because the vessels are prevented from retracting by the fibrous fascia.
  5. Because of dense fascia, hemorrhages are never extensive hence, inflammation cause little swelling but much pain.
  6. Black eye—Head injury results in collection of blood in connective tissue layer which causes generalized swelling. The blood may extend anteriorly into the root of nose and into the eyelids causing black eye.
    Figure 1.2 shows nerve and blood supply of scalp.
3
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Fig. 1.2: Nerve and blood supply of scalp
 
PREVIOUS YEAR QUESTIONS
  1. Describe scalp under following headings with diagrams:
    1. Layers
    2. Blood supply
    3. Nerve supply
    4. Lymphatic drainage
  2. Write a short note on dangerous area of scalp.
  3. Describe applied anatomy of scalp.
MULTIPLE CHOICE QUESTIONS
1. Following are the layers of scalp except:
  1. Superficial fascia
  2. Aponeurosis
  3. Pericranium
  4. Endocranium
2. Which layer is known as the “Dangerous area of scalp”:
  1. Skin
  2. Pericranium
  3. Loose areolar tissue
  4. Deep fascia
3. Most of the movements of scalp occur between:
  1. Aponeurosis and pericranium
  2. Superficial fascia and deep fascia
  3. Skin and superficial fascia
  4. Loose areolar tissue and pericranium
4. All are true about emissary veins of scalp except:
  1. Valveless
  2. Connect extracranial veins with intracranial venous sinuses
  3. Principal vein of scalp
  4. Present in loose areolar tissue
5. Which of the following arteries does not supply scalp:
  1. Supratrochlear
  2. Supraorbital
  3. Facial
  4. Occipital
6. Lymph from scalp drains into:
  1. Parotid nodes
  2. Submandibular nodes
  3. Submental nodes
  4. Jugular nodes
Answers
1. (d)
2. (c)
3. (a)
4. (c)
5. (c)
6. (a)