From the ganglion, the 3 major divisions of the trigeminal nerve emerge anteriorly and inferiorly, with the first two ophthalmic and maxillary divisions passing anteriorly to enter the cavernous sinus , and the third mandibular division descending into the foramen ovale. The ganglionic epineurium is innervated by the nervus spinosus from the mandibular division of the trigeminal nerve which re-enters the skull via the foramen spinosum.
Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Updating… Please wait. Unable to process the form. Check for errors and try again. Thank you for updating your details. Log In. Sign Up. Become a Gold Supporter and see no ads. Log in Sign up. Articles Cases Courses Quiz. About Recent Edits Go ad-free. Edit article. View revision history Report problem with Article. It is part of the trigeminal nerve , which gathers sensory stimuli from the head and face and provides nerve stimulation to the muscles that control chewing.
A nerve ganglion is a group of nerves that typically function similarly to each other and are enclosed by connective tissue. The trigeminal ganglion can be affected by a number of medical conditions, the most common of which are shingles and trigeminal neuralgia.
This ganglion can be damaged by trauma, tumors, or infections. The three sensory branches of the trigeminal nerve—the ophthalmic nerve, the maxillary nerve, and the mandibular nerve —converge at the trigeminal ganglion before the trigeminal nerve continues on to enter into the brainstem. The brainstem is physically the lowest part of the brain, located at the back of the head, right above the spine.
The trigeminal ganglion is about 2 millimeters in size and rounded in shape. It is the largest of the cranial nerve ganglia and it is the widest part of the trigeminal nerve. Everyone has two trigeminal ganglia, each of which mediates the sensation of the ipsilateral same side of the face. The trigeminal ganglion lies in a space near the top of the temporal bone, on the inside of the skull, anterior to in front of the ear.
As the name implies, it is cavelike in shape. Cerebrospinal fluid CSF surrounds the trigeminal ganglion, providing nourishment. The trigeminal ganglion is located close to the pons of the brainstem. The brainstem is composed of three sections—the pons is the middle section and it is below the midbrain and above the medulla which is continuous with the spine. The nerve fibers of the trigeminal nerve enter the brainstem at the level of the pons, which contains the root and nerve fibers of the trigeminal nerve that travel up to higher regions of the brain.
The trigeminal ganglion itself may be affected by abnormalities in nearby structures, such as an aneurysm outpouching of the internal carotid artery. An aneurysm can compress the nerve, causing symptoms of dysfunction, including pain, sensory loss, tingling, or weakness of the muscles that control chewing. The trigeminal ganglion has sensory and motor functions. It receives sensory input from the three sensory branches of the trigeminal nerve. These branches bring sensation from the face and head to the ipsilateral trigeminal ganglion, which sends the sensory messages into the brainstem.
That sensory information is transmitted from the brainstem and crosses over to the other side of the brain, eventually reaching the thalamus and then the sensory strip of the cerebral cortex on the opposite side of the brain. The motor branch of the trigeminal nerve receives its messages from the motor region of the cerebral cortex.
These messages cross over in the brainstem and pass through the trigeminal ganglion and eventually to the muscles that control chewing. The motor branch of the trigeminal nerve controls several muscles, including the temporalis, masseter, the medial and lateral pterygoids, the mylohyoid, the tensor tympani, the tensor vali palatini, and the anterior belly of the digastric muscle.
The three sensory branches of the trigeminal nerve bring in sensation to the trigeminal ganglion from the forehead, scalp, eyelids, eyes, cheeks, mouth, lips, gums, the roof of the mouth, teeth, tongue and outer part of the ear. This allows the body to detect light touch, pain, temperature, and position of these areas of the face and head.
Shingles and trigeminal neuralgia are painful conditions associated with the trigeminal ganglion. Other conditions affecting this ganglion are not as common as conditions affecting the trigeminal nerve because the ganglion is relatively small and is less likely to be injured. Nevertheless, there are several medical conditions associated with trigeminal ganglion.
Shingles is a painful condition that occurs due to the reactivation of the herpes zoster virus , which causes chickenpox. If you have had a chickenpox infection at some time in your life, the virus can remain in the body in an inactive state for many years.
The motor root runs in front of and medial to the sensory root, and passes beneath the ganglion; it leaves the skull through the foramen ovale, and, immediately below this foramen, joins the mandibular nerve. 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 give off minute branches to the tentorium cerebelli, 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 and maxillary consist exclusively of sensory fibers; the mandibular is joined outside the cranium by the motor root.
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