Anatomy of the Scalp

Anatomy of the Scalp

• The scalp is the soft tissue covering the vault of the skull.
• Extent: Anteriorly, it extends up to the eyebrows; Posteriorly, up to the superior nuchal line and the external occipital protuberance; Laterally, up to 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 blood vessels and nerves of the scalp.
• 3. Epicranial aponeurosis.
• 4. Subaponeurotic space (loose areolar tissue): Loosely connects the epicranial aponeurosis with the pericranium, allows movement of the first three layers of the scalp over the skull, and contains small arteries and emissary veins.
• 5. The pericranium (Periosteum).

Subaponeurotic Space

• Extent: Anteriorly, it extends beneath the orbicularis oculi into the eyelids; Posteriorly, up to the superior nuchal line; Laterally, up to the temporal fascia.
• Clinical importance: Bleeding in the subaponeurotic space may appear in the upper eyelids, causing a black eye.

Anatomy of the Occipitofrontalis Muscle

• It is the only muscle of the scalp.
• Consists of two frontal bellies in front and two occipital bellies behind.
• Origin: Frontal bellies arise from the skin of the forehead and the eyebrows; Occipital bellies arise from the lateral 2/3 of the highest nuchal line.
• Insertion: The frontal and occipital bellies are inserted into the epicranial aponeurosis.
• Nerve supply: The facial nerve (temporal branch for frontal bellies and posterior auricular branch for occipital bellies).
• Action: Moves the scalp forward and backward; Frontal bellies draw the scalp forward and elevate the eyebrows, while occipital bellies draw the scalp backward.

Arterial Supply of the Scalp

• In front of the auricle:
  • Supratrochlear artery and Supraorbital artery (from the ophthalmic artery, internal carotid artery).
  • Superficial temporal artery (from the external carotid artery).
• Behind the auricle:
  • Posterior auricular artery (from the external carotid artery).
  • Occipital artery (from the external carotid 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 or directly into the internal jugular vein.
• Deep veins (emissary veins): Communicate superficial veins with dural venous sinuses.

Nerve Supply of the Scalp

• Sensory nerve supply:
  • In front of the auricle:
    • Supratrochlear and Supraorbital nerves (from the ophthalmic division of the trigeminal nerve).
    • Zygomaticotemporal nerve (from the maxillary division of the trigeminal nerve).
    • Auriculotemporal nerve (from the mandibular division of the trigeminal nerve).
  • Behind the auricle:
    • Great auricular nerve (c2, 3), Lesser occipital nerve (c2), Great occipital nerve (c2), and Third occipital nerve (c3) (branches from the cervical plexus).
• Motor nerve supply: From branches of the facial nerve (temporal and posterior auricular branches).

Lymphatic Drainage of the Scalp

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

This quiz covers the anatomy of the scalp, including its definition, extent, layers, muscles, and blood supply. Students will learn about the occipitofrontalis muscle, arterial supply, venous drainage, nerve supply, and lymphatic drainage of the scalp.