The Scalp Head & Neck Unit – Lecture 4 د. حيدر جليل الأعسم
The scalp • part of the head that extends from superciliary arches anteriorly to the external occipital protuberance & superior nuchal lines posteriorly. Laterally, it continues to the zygomatic arch. • Layers of scalp: • five layers, the first three layers are intimately bound together and move as a unit (Scalp Proper) • S- Skin • C- Connective tissue (dense) (Scalp Proper) • A- Aponeurotic layer • L- Loose connective tissue • P- Pericranium
Muscle of the Scalp (Occipitofrontalis muscle) • It moves the scalp proper, wrinkle the forehead, and raise the eyebrows. It Has 2 bellies: • Frontal belly:(origin) skin & superficial fascia of the eyebrows (insertion) aponeurotic tendon & is innervated by temporal branches of the facial nerve. • Occipital belly: (origin)superior nuchal line of occipital bone & mastoid process of temporal bone (insertion) aponeurotic tendon & is innervated by posterior auricular branch of the facial nerve.
Scalp Innervation • Two main sources: 1- Cranial nerves: (Ant. to ear & vertex) By Trigeminal nerve 2- Cervical nerves: (Post. to ear & vertex) By C2 & C3 nerves.
Scalp Innervation Trigeminal branches: (Ant. to ears & vertex) A- Supratrochlear nerve: front of the forehead near the midline; B- Supra-orbital nerve: the scalp as far back as the vertex of the head; C- Zygomaticotemporal nerve: the scalp over a small anterior area of temporal region (temple) D- Auriculo-temporal nerve: the scalp over the temporal region.
Scalp Innervation Cervical nerves (C2 &C3) (Posterior to ears & vertex) A- Great auricular nerve: small area of the scalp just posterior to the ear & angle of mandible. B- Lesser occipital nerve: the scalp posterior & superior to ear C- Greater occipital nerve: posterior scalp as far as the vertex; D- Third occipital nerve: a small area of the lower part of the scalp.
Arterial Supply • The scalp has rich blood supply; • It arterial supply is from internal and external carotid arteries. Internal Carotid Artery Branches: 1- Ophthalmic artery: 2- Supratrochlear artery 3- Supra-orbital arteries • As fas as the vertex. External Carotid Artery Branches: 1- Posterior auricular artery (smallest) area of the scalp posterior to the ear; 2- Pre-auricular artery (superficial temporal artery (a terminal branch of ECA)in front of the ear & supplies most of the lateral aspect of scalp. 3- Occipital artery: large part of the posterior aspect of the scalp.
Venous Drainage • Usually follows the arteries: 1-Supratrochlear vein 2- Supra-orbital vein 3- Pre-auricular vein (superficial temporal vein) 3- Posterior auricular vein 4- Occipital vein
Lymphatic drainage • Lymphaticsin the occipital region initially drain to occipital nodes then into the upper deep cervical nodes. • Lymphatics from the upper part of the scalp drain in two directions: 1- Posterior to the vertex: to posterior auricular nodes (mastoid nodes) then into the upper deep cervical nodes; 2- Anterior to the vertex: to pre-auricular nodes (parotid nodes). • Lymphatics from the forehead to the submandibular nodes through efferent vessels that follow the facial artery.