A trigeminal ganglion (or Gasserian ganglion, or semilunar ganglion, or Gasser's ganglion) is the sensory

ganglion A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympath ...

at the base of each of the two

trigeminal nerve In neuroanatomy, the trigeminal nerve (literal translation, lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for Sense, sensation in the face and motor functions ...

s (CN V), occupying a cavity ( Meckel's cave) in the

dura mater In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous syste ...

, covering the trigeminal impression near the apex of the petrous part of the

temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears ...

Structure

It is somewhat crescent-shaped, with its convexity directed forward: Medially, it is in relation with the internal carotid artery and the posterior part of the

cavernous sinus The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica. Structure The c ...

. The

motor root In anatomy and neurology, the ventral root of spinal nerve, anterior root, or motor root is the efferent motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sourc ...

runs in front of and medial to the sensory root, and passes beneath the

; it leaves the skull through the

foramen ovale There are multiple structures in the human body with the name foramen ovale (plural: ''foramina ovalia''; Latin for "oval hole"): * Foramen ovale (heart), in the fetal heart, a shunt from the right atrium to left atrium * Foramen ovale (skull), at ...

, and, immediately below this foramen, joins the

mandibular nerve In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve ( ophthalmic nerve, maxillary nerve) which contain only ...

. The greater superficial petrosal nerve lies also underneath the ganglion. The ganglion receives, on its medial side, filaments from the carotid plexus of the sympathetic. It gives off minute branches to the

tentorium cerebelli The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes. Structure The cerebellar tentorium is an arche ...

, and to the dura mater in the middle fossa of the cranium. From its convex border, which is directed forward and lateralward, three large nerves proceed, viz., the ophthalmic (V₁),

maxillary Maxillary means "related to the maxilla (upper jaw bone)". Terms containing "maxillary" include: * Maxillary artery *Maxillary nerve In neuroanatomy, the maxillary nerve (V) is one of the three branches or divisions of the trigeminal nerve, ...

(V₂), and mandibular (V₃). The ophthalmic and maxillary consist exclusively of sensory fibers; the mandibular is joined outside the cranium by the motor root.

Clinical significance

After recovery from a primary

herpes Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold ...

infection, the

virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...

is not cleared from the body, but rather lies

dormant Dormant, "sleeping", may refer to: Science *Dormancy Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps ...

in a non-replicating state within the trigeminal ganglion. Herpes Labialis may follow from primary herpes infection/herpetic gingivostomatitis The trigeminal ganglion is damaged, by infection or surgery, in Trigeminal trophic syndrome. Trigeminal trophic syndrome causes paresthesias and anesthesia, which may lead to erosions of the nasal ala. The thermocoagulation or injection of

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids know ...

into the trigeminal ganglion has been used in the treatment of

trigeminal neuralgia Trigeminal neuralgia (TN or TGN), also called Fothergill disease, tic douloureux, or trifacial neuralgia is a long-term pain disorder that affects the trigeminal nerve, the nerve responsible for sensation in the face and motor functions such as ...

Other animals

Rodents

In rodents, the trigeminal ganglion is important as it is the first part of the pathway from the

whiskers Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...

to the brain. Cell bodies of the whisker

primary afferents Afferent nerve fibers are the axons (nerve fibers) carried by a sensory nerve that relay sensory information from sensory receptors to regions of the brain. Afferent projections ''arrive'' at a particular brain region. Efferent nerve fiber ...

are found here. These afferents are mechanoreceptor cells that fire in response to whisker deflection. There are around 26,000–43,000 cell bodies in rodent Trigeminal ganglion. It is possible that there are two distinct (or perhaps continuous) populations of cells having slowly and rapidly adapting responses to stimuli. It is found at the base of the skull and projects to trigeminal

brain stem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is cont ...

areas including principalis,

spinal trigeminal nucleus The spinal trigeminal nucleus is a nucleus in the medulla that receives information about deep/crude touch, pain, and temperature from the ipsilateral face. In addition to the trigeminal nerve (CN V), the facial (CN VII), glossopharyngeal (CN IX ...

, interpolaris, and caudalis.

Additional images

File:Gray193.png, Base of the skull. Upper surface. File:Gray777.png, Nerves of the orbit, and the ciliary ganglion. Side view. File:Gray783.png, The otic ganglion and its branches. File:Slide7nnn.JPG, Trigeminal ganglion File:Slide2ROM.JPG, Trigeminal ganglion. Deep dissection. Superior view.

References

External links

Diagram
at

University of Manitoba The University of Manitoba (U of M, UManitoba, or UM) is a Canadian public research university in the province of Manitoba.Diagram (as "Gasserian Ganglion")
at frca.co.uk * * * () {{Authority control Sensory ganglia Cranial nerves