Anatomy
Summary
Cranial nerve VII, also known as the facial nerve, has a crucial role in facial expressions and several other functions. This nerve originates from the pontomedullary junction and travels with cranial nerve VIII along the posterior cranial fossa to reach the inner ear via the internal acoustic meatus. The facial nerve then proceeds through the facial canal located within the temporal bone where it gives off branches to glands in the head and neck region, a small muscle in the middle ear, and some taste buds on the tongue.
The facial nerve then exits the skull via the stylomastoid foramen and enters the parotid gland, splitting into five terminal motor branches: temporal, zygomatic, buccal, mandibular, and cervical. In terms of function, the facial nerve controls muscles responsible for various facial expressions, and it supplies the stapedius to dampen sound transmission. In addition, it transmits sensory information from parts of the pinna and external auditory canal. Special sensory fibers of the facial nerve also convey taste from the anterior two-thirds of the tongue through the chorda tympani. Finally, parasympathetic fibers of the facial nerve innervate the sublingual and submandibular glands, facilitating salivation, and the lacrimal glands, contributing to lacrimation.
Lesson Outline
Don't stop here!
Get access to 51 more Anatomy lessons & 13 more medical school learning courses with one subscription!
FAQs
Cranial nerve VII, also known as the facial nerve, controls muscles involved in facial expression. It also has sensory and parasympathetic components, including taste sensations from the anterior two-thirds of the tongue and innervation of the sublingual and submandibular glands.
The facial nerve originates from the pontomedullary junction, where the pons and medulla of the brainstem meet.
After originating from the pontomedullary junction, the facial nerve travels along the posterior cranial fossa, through the internal acoustic meatus, and into the facial canal. Then it exits the skull via the stylomastoid foramen.
The stapedius, innervated by the facial nerve, is a small muscle that stabilizes the stapes, a tiny bone in the middle ear. It aids in damping loud noises to protect the auditory system.
The five terminal motor branches of the facial nerve (CN VII) are: temporal, zygomatic, buccal, mandibular, and cervical.
