The geniculate ganglion (from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''genu'', for "knee") is a bilaterally paired special sense ganglion of the intermediate nerve component of the facial nerve (CN VII). It is situated within

facial canal The facial canal (also known as the Fallopian canal) is a Z-shaped canal in the temporal bone of the skull. It extends between the internal acoustic meatus and stylomastoid foramen. It transmits the facial nerve (CN VII) (after which it is nam ...

of the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

. It contains cell bodies of first-order unipolar

sensory neuron Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduc ...

s which convey gustatory (taste) afferents from taste receptors of the anterior two-thirds of the tongue by way of the

chorda tympani Chorda tympani is a branch of the facial nerve that carries gustatory (taste) sensory innervation from the front of the tongue and parasympathetic ( secretomotor) innervation to the submandibular and sublingual salivary glands. Chorda tymp ...

, and of the

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...

by way of the greater petrosal nerve, From the ganglion, the proximal fibres proceed to the gustatory (i.e. superior/rostral) part of the solitary nucleus where they synapse with second-order neurons.

Anatomy

Structure

The geniculate ganglion is conical in shape. The greater petrosal nerve diverges from CNVII and the lesser petrosal nerve diverges from CN IX at the geniculate ganglion.

Relations

It is located close to the internal auditory meatus. It is covered superiorly by the

petrous part of the temporal bone The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three ...

(which is sometimes absent over the ganglion).

Clinical significance

The geniculate ganglion is an important surgical landmark near the internal auditory meatus.

Herpes zoster oticus

The geniculate ganglion may become inflamed due herpes zoster virus virus infection. Swelling of the ganglion may result in facial palsy ( Ramsay Hunt syndrome). The syndrome presents with intense pain in one ear that is followed by a vesicular rash around the

ear canal The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the auricle to the eardrum and is about in length and in diameter. S ...

Additional images

File:Gray788.png , Plan of the facial and intermediate nerves and their communication with other nerves.

References

External links

* () * () {{Authority control Nervous ganglia of the head and neck Gustatory system Sensory ganglia Otorhinolaryngology Cranial nerves Facial nerve