2. Glossopharyngeal nerve.
Introduction.
The
glossopharyngeal nerve is the 9th cranial nerve (CN IX). It is one of the
four cranial nerves that has sensory, motor, and parasympathetic
functions. It originates from the medulla oblongata and terminates in
the pharynx. These nerves start in your brainstem. They connect to
organs, muscles and other structures in your mouth and throat. These
nerves are paired — there’s one on each side.
3. Anatomy of glossopharyngeal nerve.
• The glossopharyngeal nerve starts in the lower part of your brainstem
(medulla oblongata). It passes through many structures in your neck before
reaching your pharynx (throat). Its path
includes:
• Exiting your skull through a small opening (jugular foramen).
• Traveling down your neck alongside your jugular vein.
• Going behind the styloid process, a pointy bone in your skull below your
ear.
• Curving forward and touching the stylopharyngeus (near your throat).
• Passing under the hyoglossus muscle. This muscle helps you lower your
tongue and pull it toward the back of your mouth.
4. Function
There are many glossopharyngeal nerve functions. The glossopharyngeal nerve affects
muscles, organs and body processes near your throat, such as the:
Carotid sinus: This hollow area helps blood drain from your brain into the carotid artery in
your neck. It has a role in regulating blood pressure.
Middle ear: Sensory nerve fibers enable you to detect fullness from fluid buildup. You can
also feel pain from an ear infection.
Parotid (saliva) gland: CN IX decreases saliva production when you finish eating.
Part of the tongue: The glossopharyngeal nerve helps you taste food in the back third of
your tongue.
Stylopharyngeus muscle: A long muscle that runs down part of your throat. CN IX connects
to this muscle to lift the voice box (larynx) and nearby throat (pharynx). This makes it
possible to swallow.
Tonsils: Sensory nerve fibers help you sense pain from a sore throat or swelling due to an
infection.
5. Complications of glossopharyngeal nerve
What happens if the glossopharyngeal nerve is damaged?
Glossopharyngeal nerve lesions produce difficulty swallowing; impairment of
taste over the posterior one-third of the tongue and palate; impaired
sensation over the posterior one-third of the tongue, palate, and pharynx.
Also Complications of GPN may include:
Slow pulse and fainting may occur when pain is severe
Damage to the carotid artery or internal jugular artery due to injuries, such
as a stab wound, that may be associated with GPN
Difficulty in swallowing food and speaking
Side effects of the medicines used.
6. References
1.Sonnet J, Lopez-Ojeda W. StatPearls [Internet]. StatPearls Publishing;
Treasure Island (FL): Dec 9, 2022. Neuroanatomy, Cranial Nerve. [PubMed]
2.Singh O, M Das J. StatPearls [Internet]. StatPearls Publishing; Treasure
Island (FL): Apr 3, 2023. Anatomy, Head and Neck: Jugular Foramen.
[PubMed]
3.Sakamoto Y. Morphological Features of the Glossopharyngeal Nerve in the
Peripharyngeal Space, the Oropharynx, and the Tongue. Anat Rec (Hoboken).
2019 Apr;302(4):630-638. [PubMed]
