For some cranial nerves, the name tells us the function. The prefix "glosso-" means relating to the tongue, and the suffix "-pharyngeal" means relating to the pharynx, or throat. Therefore, the glossopharyngeal nerve, also known as the ninth cranial nerve, has a role in both sensation and movement of the tongue and the throat. Learn what this important nerve does for your oral cavity.
Anatomy of the Glossopharyngeal Nerve
The University of Texas McGovern Medical School explains that the ninth cranial nerve is responsible for sensory fibers in the soft palate (roof of the mouth), the upper pharynx (throat), the tonsils and the back portion of the tongue. It also controls some motor fibers that help produce saliva as part of the parasympathetic nervous system, the system that's active when your body is resting and digesting. Finally, it helps move the throat during swallowing and talking, according to a review in the Journal of Neurosciences in Rural Practice. Because this nerve includes fibers with motor (movement) and sensory functions, doctors call it a mixed nerve.
The ninth cranial nerve originates in a part of the brainstem called the medulla oblongata, reports the Journal of Neurosciences in Rural Practice review. It exits the base of the skull at an opening called the jugular foramen.
Identifying Problems With the Ninth Cranial Nerve
When you listen to your voice, take note of any hoarseness, whispering or nasal tone to your speech. When you take a sip of water, do you feel a choking sensation or have difficulty swallowing? Perhaps you no longer have a gag reflex or you are experiencing trouble with taste. These sensations can point to cranial nerve dysfunction, explains the Journal of Neurosciences in Rural Practice review. If you have any of these symptoms, your dentist or doctor may ask you to say "ah" to see if your palate (the roof of your mouth) lifts up normally, notes the University of Texas McGovern Medical School.
Unfortunately, the Journal of Neurosciences in Rural Practice review determined that problems with this nerve often involve other cranial nerves, too. Conditions like tumors, meningitis, Lyme disease and Guillain-Barré syndrome can impact multiple cranial nerves in your head and neck, as outlined by Amboss.
Glossopharyngeal Neuralgia and Other Conditions
One rare condition unique to the ninth cranial nerve is glossopharyngeal neuralgia. Similar to trigeminal neuralgia, this condition causes sudden, brief episodes of pain. Merck Manuals explains that symptoms may include sharp pain at the back of the throat, back of the tongue or middle part of the ear. The pain may be triggered by chewing, talking, yawning or swallowing. This type of neuralgia is sometimes caused by an artery or tumor compressing the nerve, but it often has no clear explanation. Glossopharyngeal neuralgia most commonly affects men over the age of 40, Merck Manuals notes.
The Journal of Neurosciences in Rural Practice review reports that in rare cases, diphtheria and tonsil removal can cause problems with the glossopharyngeal nerve. Signs of a problem may include tongue weakness or an inability to move or feel your palate or throat. A review published in Parkinsonism & Related Disorders found that Parkinson's disease can also affect the ninth cranial nerve.
Diagnosis and Treatment
If you think something is wrong with one of the nerves in your face, your doctor or dentist will usually ask you to explain your symptoms and perform a clinical exam on your head and neck to locate the source of the problem. Your doctor will examine you for tumors, systemic conditions and any history of injuries that could have affected your cranial nerves.
If your facial pain could be the result of glossopharyngeal neuralgia, Merck Manuals reports that your medical professional may use MRI scans to make a diagnosis. Then, they will offer treatments such as anticonvulsant medications or local anesthesia. In severe cases, surgery can help take pressure off the nerve.
The glossopharyngeal nerve plays an important role in your everyday life. If you are experiencing any numbness or pain in your mouth or throat and can't figure out why, talk to your dentist or doctor.