Microsurgical anatomy of the facial nerve

Abstract

The facial nerve connections and pathways from the cortex to the brainstem are intricate and complicated. The extra-axial part of the facial nerve leaves the lateral part of the pontomedullary sulcus and enters the temporal bone through the internal acoustic meatus. In the temporal bone, the facial nerve branches into fibers innervating the glands and tongue. After it emerges from the temporal bone it supplies various facial muscles. It contains a motor, general sensory, special sensory, and autonomic components. The physician needs comprehensive knowledge of the anatomy and courses of the facial nerve to diagnose and treat lesions and diseases of it so that surgical complications due to facial nerve injury can be avoided. This review describes the microsurgical anatomy of the facial nerve and illustrates its anatomy in relation to the surrounding bone, connective, and neurovascular structures. K E Y W O R D S anatomy, facial nerve, labyrinth, temporal bone The course of the facial nerve is one of the most intricate among cranial nerves. The facial nerve has a motor and sensory roots, the latter being the intermediate nerve. The motor root supplies the muscles of the face, scalp, and auricle, and the buccinator, platysma, stapedius, stylohyoid, and the posterior belly of the digastric muscle. The sensory root conveys the chorda tympani from the tongue, palatine, and greater petrosal nerve, and taste fibers from the soft palate. It also carries the preganglionic parasympathetic (secretomotor) innervation of the submandibular and sublingual salivary glands, lacrimal glands, and glands of the nasal and palatine mucosa. Clinicians, including neurosurgeons, otologists, and head and neck surgeons need a comprehensive knowledge of the facial nerve. This nerve is divided into eight segments: intra-brainstem, root exit zone, cisternal, meatal, labyrinthine, tympanic, mastoid, and extra-temporal.

Management of non-vestibular schwannomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section Part II: Trigeminal and facial nerve schwannomas (CN V, VII)

“…The facial nerve can be divided into segments: cisternal, meatal (internal acoustic canal), labyrinthine, tympanic, mastoid, and extra-temporal [55,86]. The course of the nerve is complex with important branches along it, such as the greater superficial petrosal nerve (GSPN), the posterior auricular nerve, and the five distal branches.…”

Anatomical description of the extratemporal facial nerve under high-definition system: a microsurgical study in rats

“…This makes it difficult to dissect it without damaging part of it, due to its intrinsic relationship with the adjacent tissue. Some authors report the need to remove part of the temporal bone to facilitate surgical access [20][21][22] , but in this study the cranial bones were preserved. It is noteworthy that rats do not have an internal jugular vein; thus, all cranial drainage occurs through tributary veins of the external jugular vein, which has a clear path laterally to almost all branches that make up the facial nerve 26,27 .…”

Incidence of Facial Nerve Palsy in Pregnancy

“…The facial nerve is formed of a motor root (containing motor fibers to muscles of the face) and the nervus intermedius. The nervus intermedius contains sensory fibers for testing and parasympathetic fibers for lacrimal and salivary glands [ 1 , 2 ]. The nerve course is divided into four segments: intracranial, intrameatal, intratemporal, and extratemporal.…”

“…The facial nerve is anterior and superior to the digastric muscles. The facial nerve is superficial and anterior to the styloid process [ 2 , 5 , 8 ].…”