Anatomy of the Scalp

Anatomy of the Scalp

• Definition: The scalp is the soft tissue covering the vault of the skull.
• Extent:
  • Anteriorly: the eyebrows
  • Posteriorly: the superior nuchal line and the external occipital protuberance
  • Laterally: the superior temporal lines

Layers of the Scalp

• 1. Skin: Has hairs and numerous sebaceous glands
• 2. Superficial fascia (dense connective tissue):
  • Binds the skin tightly to the aponeurosis
  • Contains the blood vessels and the nerves of the scalp
• 3. Epicranial aponeurosis
• 4. Subaponeurotic space (loose areolar tissue):
  • Contains loose areolar tissue
  • Loosely connects the epicranial aponeurosis with the pericranium
  • Allows the movement of the first 3 layers of the scalp over the skull
  • Contains a few small arteries and emissary veins
• 5. The pericranium (Periosteum)

Occipitofrontalis Muscle

• Consists of 2 frontal bellies in front and 2 occipital bellies behind
• Origin:
  • Frontal bellies: from the skin of the forehead and the eyebrows
  • Occipital bellies: from the lateral 2/3 of the highest nuchal line
• Insertion: the frontal and occipital bellies are inserted to the epicranial aponeurosis
• Nerve supply: the facial nerve
  • Frontal bellies: by the temporal branch
  • Occipital bellies: by the posterior auricular branch
• Action:
  • Both frontal and occipital bellies move the scalp forward and backward
  • Frontal bellies draw the scalp forwards
  • Occipital bellies draw the scalp backward
  • Frontal bellies elevate the eyebrows and are responsible for transverse wrinkles of the forehead

Arterial Supply of the Scalp

• In front of the auricle:
  • Supratrochlear artery
  • Supraorbital artery
  • Superficial temporal artery
• Behind the auricle:
  • Posterior auricular artery
  • Occipital artery

Venous Drainage of the Scalp

• Superficial veins:
  • Supraorbital vein and Supratrochlear veins unite to form the facial vein
  • Superficial temporal vein unites with the maxillary vein to form the retromandibular vein
  • Posterior auricular vein unites with the posterior division of the retromandibular vein to form the external jugular vein
  • Occipital vein drains into the suboccipital venous plexus which drains into the vertebral vein
• Deep veins (emissary veins):
  • Present in the subaponeurotic space
  • Communicate the superficial veins of the scalp with the dural venous sinuses

Nerve Supply of the Scalp

• Sensory nerve supply:
  • In front of the auricle:
    • Supratrochlear and Supraorbital nerves: branches from the ophthalmic division of the trigeminal nerve
    • Zygomaticotemporal nerve: branch from the maxillary division of the trigeminal nerve
  • Behind the auricle:
    • Great auricular nerve (c2, 3)
    • Lesser occipital nerve (c2)
    • Great occipital nerve (c2)
    • Third occipital nerve (c3)
• Motor nerve supply:
  • From branches of the facial nerve
  • In front of the auricle: the temporal branch of the facial nerve supplies the frontal belly of the occipitofrontalis
  • Behind the auricle: the posterior auricular branch of the facial nerve supplies the occipital belly of the occipitofrontalis

Lymphatic Drainage of the Scalp

• In front of the auricle: The anterior part (forehead) and lateral part of the scalp drain into superficial parotid (preauricular) lymph nodes
• Behind the auricle: The posterior part of the scalp drains into mastoid and occipital lymph nodes