Geniculate nucleus

Geniculate ganglion is a sensory ganglion of the facial nerve (VII cranial nerve) located in the facial canal of the temporal bone. It receives sensory fibers from the anterior two-thirds of the tongue for taste and from the external ear for pain and temperature.

Anatomy

The geniculate ganglion is a collection of nerve cell bodies (a ganglion) of the facial nerve located in the facial canal of the temporal bone. It is one of several ganglia associated with cranial nerves and is unique in that it contains both sensory and motor neurons.

The ganglion is located at the first genu (bend) of the facial nerve, at the transition between the labyrinthine segment and the tympanic segment. It is closely associated with the labyrinthine artery, which often passes through it.

Function

The geniculate ganglion contains the cell bodies of sensory neurons that carry taste information from the anterior two-thirds of the tongue via the chorda tympani, and sensory neurons that carry pain and temperature information from the external ear.

The ganglion also contains the cell bodies of preganglionic parasympathetic neurons that innervate the submandibular and sublingual glands, as well as the lacrimal gland. These neurons send their axons out of the ganglion in the greater petrosal nerve (for the lacrimal gland) and the chorda tympani (for the submandibular and sublingual glands).

Clinical significance

Damage to the geniculate ganglion can result in a loss of taste sensation from the anterior two-thirds of the tongue and a decreased production of saliva and tears. It can also cause Bell's palsy, a condition characterized by paralysis of the muscles of facial expression on one side of the face.

See also

• Facial nerve
• Chorda tympani
• Labyrinthine artery
• Bell's palsy