Welcome to 2 minute neuroscience, where I explain neuroscience topics in 2 minutes or
In this installment I will discuss the facial nerve.
The facial nerve, also known as cranial nerve VII, is best known for its role in controlling
the muscles of facial expression, as well as a number of other muscles of the face and
head such as certain muscles involved with swallowing and jaw movement, muscles of the
external ear, and the stapedius muscle, which is found in the middle ear and is involved
with dampening loud noises.
The facial nerve also receives sensory information from the outer ear and from the taste buds
on the anterior two-thirds of the tongue, and it supplies most major glands in the head,
including the lacrimal glands for tear production, the submandibular and sublingual salivary
glands, and the mucous glands of the nose, paranasal sinuses, and palate.
The facial nerve is associated with several nuclei in the brainstem.
The motor portion of the facial nerve originates in the facial motor nucleus in the pons.
The portion of the nerve that supplies the glands mentioned previously originates from
the superior salivatory nucleus in the pons.
Taste information travels to the nucleus of the solitary tract in the medulla.
And the sensory information from the outer ear travels to the spinal trigeminal nucleus
in the medulla.
Facial nerve damage can cause a variety of symptoms, but the most recognizable of them
is weakness and/or paralysis of the muscles of facial expression on the same side of the
head that the damaged nerve supplies.
The patient’s mouth on the affected side may droop, and he may be unable to close the
eye on the affected side.
In most cases of facial nerve palsy, the cause of the dysfunction is not known; when this
is the case it is referred to as Bell’s palsy.