Anatomy of the SCALP

SCALP

• The scalp is the skin and underlying subcutaneous tissue covering the calvaria between superior nuchal lines and supraorbital margins.
• It is formed of five layers: skin, connective tissue, aponeurosis, loose areolar tissue, and pericranium.
• The skin is hairy and thick, containing sweat and sebaceous glands, and is rich in arteries, veins, and lymph vessels.
• The connective tissue is thick and dense, containing sensory nerves and having a rich vascular supply.
• The aponeurosis is a dense tendinous structure that muscles forming the epicranius muscle attach to.

Layers of the SCALP

• The first three layers of the scalp (skin, connective tissue, and aponeurosis) are firmly attached together and are collectively referred to as the scalp proper.
• The loose areolar tissue layer has a spongy structure, contains few arteries and emissary veins, and extends between the superficial veins of the scalp and the diploic veins of the skull bones.
• The pericranium layer is the periosteum of the skull bones, formed of dense connective tissue, and supplies the skin of the forehead and anterior part of the scalp.

Nerves of the SCALP

• The supratrochlear nerve supplies the skin on the middle part of the forehead.
• The trigeminal nerve (CN V) supplies a small area of skin lateral to the upper eyelid, also related to part of the conjunctiva.
• The trigeminal nerve (CN V) has three main branches: ophthalmic nerve (V1), maxillary nerve (V2), and mandibular nerve (V3).
• The maxillary nerve (V2) passes through the foramen rotundum and enters the pterygopalatine fossa, and its branches supply the maxillary sinus, teeth of the upper jaw, and gingiva.

Arteries and Veins of the SCALP

• Arteries of the scalp are branches from the external carotid artery and ophthalmic artery (branch of internal carotid).
• Veins of the scalp follow the arteries and drain into the occipital vein, posterior auricular vein, superficial temporal vein, supratrochlear vein, and supraorbital vein.

Lymphatics of the SCALP

• Lymphatics drain into the submental, submandibular, parotid, mastoid, retroauricular, and occipital lymph nodes.
• These lymph nodes mainly drain into the deep cervical lymph nodes.

FACE

• The face has no deep fascia, but the superficial fascia is thicker in certain regions.
• Muscles of the face lie in the subcutaneous tissue, extend from bone or facia to skin, and enable us to express our mood.

Facial Nerve (CN VII)

• The facial nerve leaves the CNS and enters the temporal bone through the internal acoustic meatus.
• It follows an "S" shaped route inside the temporal bone and leaves the skull through the stylomastoid foramen.
• The facial nerve has five terminal branches: temporal, zygomatic, buccal, marginal mandibular, and cervical.

Branching of the Facial Nerve

• The greater petrosal nerve arises at the beginning of the facial canal and carries presynaptic parasympathetic fibers to the pterygopalatine ganglion.
• The nerve to the stapedius muscle and the chorda tympani branch within the facial canal.
• The posterior auricular nerve and motor branch innervate the stylohyoid muscle and the posterior belly of the digastric muscle.

Trigeminal Nerve (CN V)

• The trigeminal nerve has three main branches: ophthalmic nerve (V1), maxillary nerve (V2), and mandibular nerve (V3).
• The ophthalmic nerve (V1) is a sole sensory nerve that enters the orbit through the superior orbital fissure and supplies branches to the eyeball and superior part of the nasal cavity.
• The maxillary nerve (V2) is a sensory nerve that passes through the foramen rotundum and enters the pterygopalatine fossa.
• The mandibular nerve (V3) is a sensory and motor nerve that leaves the skull through the foramen ovale and enters the infratemporal fossa.

Arteries and Veins of the FACE

• The facial artery and superficial temporal artery are branches of the external carotid artery.
• The maxillary vein and superficial temporal vein unite to form the retromandibular vein.
• The retromandibular vein gives two branches, which unite with the posterior auricular vein and the facial vein, and drains into the internal jugular vein.

Lymphatic Drainage of the FACE

• All of the lymphatics finally drain into the deep cervical lymph nodes.