Scalp, Face & Parotid Anatomy Quiz

Scalp, Face & Parotid - Learning Outcomes

• List the layers of the scalp, its blood supply, and bleeding from the scalp
• Describe the superficial temporal artery and the facial artery
• Describe the veins of the face and temporal region
• Identify the major muscles of the face and jaw
• Describe the seventh cranial nerve: its relationships, lesions, and testing
• Describe the parotid gland and its duct, their relationships and clinical conditions, and its secretomotor innervation
• Describe the anatomy of the ophthalmic division of the trigeminal nerve, including how their integrity is tested clinically.

The Scalp

• Skin: Thin, except in the occipital region with abundance of sweat, sebaceous glands, and hair follicles. It has a rich arterial supply, good venous, and lymphatic drainage.
• Connective tissue layer/sub-cutaneous tissue: Composed of numerous blood vessels and nerves. Wounds in this layer bleed profusely because blood vessels cannot retract due to the fibrous tissue.
• Aponeurosis: A tendinous sheet of occipitofrontalis and loose connective tissue. It is considered a dangerous layer of the scalp.
• Periosteum: The outer layer of the cranium. Cephalohematoma is often a part of this layer.

Blood Supply to the Scalp

• Arteries: Supratrochlear, supra-orbital, superficial temporal, posterior auricular, and occipital arteries.
• Veins: These veins connect to the skull bones and the cranial cavity, known as emissary veins. Blood in the emissary veins flows from superficial to deep, allowing infection to spread into the intracranial cavity.

Muscles of the Face

• Facial muscles are used for facial expression.
• These muscles originate from the facial bones and are attached to the skin.
• The muscles develop from the mesoderm of the second pharyngeal arch and are supplied by the facial nerve.
• Facial muscles act as sphincters or dilators of orifices (orbit, nose and mouth).

Muscles Around the Orbit

• Orbicularis oculi
• Levator palpebrae superioris
• Corrugator supercilii

Muscles Around the Nose

• Compressors naris
• Dilators naris
• Procerus
• Levator labii superioris alaeque nasi

Muscles Around the Mouth

• Orbicularis oris
• Levator labii superioris
• Zygomaticus minor and major
• Levator anguli oris
• Risorius
• Depressor anguli oris
• Depressor labii inferioris
• Mentalis
• Buccinator (muscle of the cheek)

Platysma

• Platysma is a superficial muscle that lies just deep to the skin.
• It is innervated by the facial nerve.
• Its contraction tightens the skin, pulls the corners of the mouth down, and lifts the skin over the upper thorax.
• Expressive actions including shock, disbelief, and horror.

Facial Nerve

• A mixed cranial nerve (CN VII) with both sensory and motor roots.
• Has parasympathetic function.
• Attached to the lower border of the pons between the olive and inferior cerebellar peduncle.
• Branches of the Facial Nerve: Temporal, Zygomatic, Buccal, Mandibular, Cervical.

Parotid Gland

• Largest salivary gland composed mostly of serous acini.
• Enclosed by thick parotid fascia derived from the investing layer of the deep cervical fascia.
• Secretes 25% of saliva (serous - watery secretions).
• Structures within the parotid gland: External carotid artery, maxillary and superficial temporal arteries, retromandibular vein, facial nerve, and parotid lymph nodes.
• Parotid duct (Stensen duct): Thick-walled duct, runs forward on masseter. Opens into vestibule of mouth opposite the crown of the upper second molar tooth.
• Parasympathetic innervation comes from the inferior salivatory nucleus leaving with the glossopharyngeal nerve (IX).

Clinical Applications (Parotid Gland)

• Parotid gland tumor
• Parotitis (inflammation): Inflammatory or infective (i.e., stones in the duct, bacterial or viral) - Mumps.
• Frey's syndrome: A rare condition often following trauma or surgery to the auriculotemporal nerve in the parotid area. Patients often complain of redness and sweating of the cheek and temporal areas when eating or even thinking of eating.

Branches of the External Carotid Artery

• Branches from the anterior surface: Superior thyroid, Lingual, Facial
• Branches from the posterior surface: Occipital, Posterior auricular
• Branches from the deep surface: Ascending pharyngeal
• Terminal branches: Maxillary, Superficial temporal

Jaw Muscles (Muscles of Mastication)

• Massester
• Temporalis
• Medial pterygoid
• Lateral pterygoid
• Innervated by the trigeminal nerve.

Lymphatic Drainage (Scalp, Face, & Parotid)

• Pre-auricular/parotid nodes
• Submental nodes
• Submandibular nodes
• Jugulo-omohyoid node
• Occipital nodes
• Mastoid nodes
• Jugulodigastric node
• Superficial cervical nodes
• Internal jugular vein
• Deep cervical nodes
• External jugular vein

Testing Motor Function of the Facial Nerve

• Instructions on how to test the motor function.
• Procedures to be followed during the test.