Innervation of the Face
Fig. 32.1 Motor innervation of the face
Left lateral view. Five branches of the facial nerve (CN VII) provide motor innervation to the muscles of facial expression. The mandibular division of the trigeminal nerve (CN V3) supplies motor innervation to the muscles of mastication.
Fig. 32.2 Sensory innervation of the face
Arteries of the Head & Neck
The head and neck are supplied by branches of the common carotid artery. The common carotid splits at the carotid bifurcation into two branches: the internal and external carotid arteries. The internal carotid chiefly supplies the brain (p. 606), although its branches anastomose with the external carotid in the orbit and nasal septum. The external carotid is the major supplier of structures of the head and neck.
Fig. 32.3 Internal carotid artery
Left lateral view. The most important extra-cerebral branch of the internal carotid artery is the ophthalmic artery, which supplies the upper nasal septum (p. 524) and the orbit (p. 512). See pp. 608–609 for arteries of the brain.
Carotid artery atherosclerosis
The carotid artery is often affected by atherosclerosis, a hardening of arterial walls due to plaque formation. The examiner can determine the status of the arteries using ultrasound. Note: The absence of atherosclerosis in the carotid artery does not preclude coronary heart disease or atherosclerotic changes in other locations.
Fig. 32.4 External carotid artery: Overview
Left lateral view.
External Carotid Artery: Anterior, Medial & Posterior Branches
Fig. 32.5 Anterior and medial branches
Left lateral view. The arteries of the anterior aspect supply the anterior structures of the head and neck, including the orbit (p. 540), ear (p. 534), larynx (p. 575), pharynx (p. 556), and oral cavity. Note: The angular artery anastomoses with the dorsal nasal artery of the internal carotid (via the ophthalmic artery).
Fig. 32.6 Posterior branches
Left lateral view. The posterior branches of the external carotid artery supply the ear (p. 534), posterior skull (p. 499), and posterior neck muscles (p. 585).
External Carotid Artery: Terminal Branches
The terminal branches of the external carotid artery consist of two major arteries: superficial temporal and maxillary. The superficial temporal artery supplies the lateral skull. The maxillary artery is a major artery for internal structures of the face.
Fig. 32.7 Superficial temporal artery
Left lateral view. Inflammation of the superficial temporal artery due to temporal arteritiscan cause severe headaches. The course of the frontal branch of the artery can often be seen superficially under the skin of elderly patients.
Fig. 32.8 Maxillary artery
Left lateral view. The maxillary artery consists of three parts: mandibular (blue), pterygoid (green), and pterygopalatine (yellow).
Middle meningeal artery
The middle meningeal artery supplies the meninges and overlying calvaria. Rupture of the artery (generally due to head trauma) results in an epidural hematoma.
The sphenopalatine artery supplies the wall of the nasal cavity. Excessive nasopharyngeal bleeding from the branches of the sphenopalatine artery may necessitate ligationofthe maxillary artery in the pterygopalatine fossa.
Veins of the Head & Neck
Fig. 32.9 Veins of the head and neck
Left lateral view. The veins of the head and neck drain into the brachio-cephalicvein. Note: The left and right brachiocephalic veins are not symmetrical.
Fig. 32.10 Deep veins of the head
Left lateral view. Removed: Upper ramus, condylar and coronoid processes of mandible. The pterygoid plexus is a venous network situated between the mandibular ramus and the muscles of mastication. The cavernous sinus connects branches of the facial vein to the sigmoid sinuses.
Fig. 32.11 Veins of the occiput
Posterior view. The superficial veins of the occiput communicate with the dural venous sinuses via emissary veins that drain to diploic veins (calvaria, p. 457). Note: The external vertebral venous plexus traverses the entire length of the spine (p. 611).
Topography of the Superficial Face
Fig. 32.12 Superficial neurovasculature of the face
Anterior view. Removed: Skin and fatty subcutaneous tissue; muscles of facial expression (leftside).
Fig. 32.13 Superficial neurovasculature of the head
Left lateral view.
Topography of the Parotid Region & Temporal Fossa
Fig. 32.14 Parotid region
Left lateral view. Removed: Parotid gland, sternocleidomastoid, and veins of the head. Revealed: Parotid bed and carotid triangle.
Fig. 32.15 Temporal fossa
Left lateral view. Removed: Sternocleidomastoid and masseter. Revealed: Temporal fossa and temporomandibular joint (p. 540).
Topography of the Infratemporal Fossa
Fig. 32.16 Infratemporal fossa: Superficial layer
Left lateral view. Removed: Ramus of mandible. Note: The mylohyoid nerve (see p. 547) branches from the inferior alveolar nerve just before the mandibular foramen.
Fig. 32.17 Deep layer
Left leteral view. Removed: Lateral pterygold muscle (both heads). Revealed: Deep infratemporal fossa and mandibular nerve as it enters the mandibular canal via the foramen ovale in the roof of the fossa.
Fig. 32.18 Mandibular nerve (CN V3) in the infratemporal fossa
Topography of the Pterygopalatine Fossa
The pterygopalatine fossa is a small pyramidal space just inferior to the apex of the orbit. It is continuous with the infratemporal fossa, with no clear line of demarcation between them. The pterygopalatine fossa is a crossroads for neurovascular structures traveling between the middle cranial fossa, orbit, nasal cavity, and oral cavity.
Fig. 32.19 Arteries in the pterygopalatine fossa
Left lateral view into area. The maxillary artery passes over the lateral pterygoid in the infratemporal fossa (see Fig. 32.16) and enters the pterygopalatine fossa through the pterygomaxillary fissure.
The maxillary division of the trigeminal nerve (CN V2, see p. 477) passes from the middle cranial fossa through the foramen rotundum into the pterygopalatine fossa. The parasympathetic pterygopalatine ganglion receives presynaptic fibers from the greater petrosal nerve (the parasympathetic root of the nervus intermedius branch of the facial nerve). The preganglionic fibers of the pterygopalatine ganglion synapse with ganglion cells that innervate the lacrimal, small palatal, and small nasal glands. The sympathetic fibers of the deep petrosal nerve (sympathetic root) and sensory fibers of the maxillary nerve (sensory root) pass through the pterygopalatine ganglion without synapsing.
Fig. 32.20 Nerves in the pterygopalatine fossa
Left lateral view.