31 - Facial Nerve Block

Abstract

The facial nerve provides both motor and sensory fibers to the head. The facial nerve arises from the brain stem at the inferior margin of the pons. After leaving the pons, the fibers of the facial nerve travel across the subarachnoid space and enter the internal auditory meatus to pass through the petrous temporal bone. The nerve then exits the base of the skull via the stylomastoid foramen. It passes downward and then turns forward to pass through the parotid gland, where it divides into fibers that provide innervation to the muscles of facial expression. Facial nerve block is useful in the diagnosis and treatment of painful conditions and facial spasms in areas subserved by the facial nerve, including geniculate neuralgia, atypical facial neuralgias, the pain associated with Bell palsy, herpes zoster involving the geniculate ganglion (Ramsay Hunt syndrome), and spastic conditions such as hemifacial spasm.