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Body Surface

The primary surface landmarks of the face are associated with the eye (supraorbital margin, infraorbital margin, palpebral fissure, medial commissure, lateral commissure, and lacrimal caruncle, lake and punctum), external ear (helix, antihelix, concha, external auditory meatus, tragus, antitragus and lobule), mouth (philtrum, vermillion border, oral fissure and angle of the mouth [buccal angle]), nose (nostril, septum and nasion), zygomatic arch, and mandible (angle and inferior margin). Branches of the ophthalmic (lacrimal, supraorbital, supratrochlear and external nasal), maxillary (infraorbital, zygomaticotemporal and zygomaticofacial) and mandibular (auriculotemporal, buccal and mental) divisions of the trigeminal nerve, and the great auricular nerve innervate the skin overlying the face.

Skeleton and Joints

The bones associated with the face are the frontal, zygomatic, nasal, maxilla and mandible. There are sutures (fibrous joints) between the adjacent bones.

Organization

Most of the face lacks the thick, fibrous deep fascia that covers the neck and extremities. There is a layer (parotid) of deep fascia covering the parotid gland near the ear. There are multiple layers of superficial fascia (continuous below with the platysma) of varying thickness deep to the skin and superficial to the level of the five facial nerve branches. The facial nerve branches gain access to the face by passing through and emerging from the anterior aspect of the parotid gland. The parotid gland, a major salivary gland, is positioned anterior to the ear and posterior and lateral to the masseter and ramus of the mandible. Its duct passes anterior to drain into the oral cavity by piercing the buccinator muscle. The craniofacial muscles (muscles of facial expression) are different than the skeletal muscles of the extremities. They lack a deep fascial epimysium (covering of deep fascia) and attach in part to the skin. A few of the muscles (buccinator) have a thin layer of deep fascia (buccopharyngeal fascia). The scalp consists of five layers (skin, subcutaneous tissue, the occipitofrontalis aponeurosis, loose areolar tissue and the cranial periosteum). The blood vessels and nerves lie in the subcutaneous tissue layer superficial to the aponeurosis.

Muscles

The craniofacial muscles (muscles of facial expression) are divided into groups moving the scalp (frontalis and occipitalis) or ears, and muscles contributing to the sphinchters around the oral cavity (buccinator, depressor anguli oris, depressor labii inferioris, levator anguli oris, levator labii superioris, levator labii superioris alequae nasi, mentalis, orbicularis oris, risorius, and zygomaticus major and minor) and orbit (corrugator supercilii, orbicularis oculi and procerus).

Innervation

Branches of the facial nerve (cranial nerve VII) innervate (motor) the craniofacial muscles. The trigeminal nerve (cranial nerve V) has three major divisions or nerve branches, the ophathalmic, maxillary and mandibular. Branches of the ophthalmic, maxillary and mandibular nerves innervate (sensory) the skin, fascia and muscles of the face. The parotid gland is innervated by postganglionic sympathetic axons from the superior cervical ganglion and postganglionic parasympathetic axons from the otic ganglion.

Blood Supply

Branches of the facial, superficial temporal, maxillary and ophthalmic arteries are the primary blood supply of the face. The face is drained by tributaries of the corresponding veins.