The glossopharyngeal nerve is a paired set of nerves, which is part of the 24 cranial nerves. These nerves are arranged in twelve pairs, of which the glossopharyngeal is the ninth. The pairs of cranial nerves, in order, are: the olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, and hypoglossal.
The glossopharyngeal nerve connects to the brainstem at the upper medulla, travels through the base of the skull at the jugular foramen, and ends in the mouth in the mucous glands, palatine tonsil, and the base of the tongue. It splits into various branches: the tonsillar, tympanic, stylopharyngeal, carotid sinus nerve, lingual, communication branch to the vagus nerve, and a branch to the back third of the tongue.
The glossopharyngeal nerve has many functions, including receiving various forms of sensory fibers from parts of the tongue, carotid body, the tonsils, the pharynx, and the middle ear. It also supplies parasympathetic fibers (those that aid the body with rest and digestion processes) to the parotid gland (a major salivary gland) and motor fibers to the stylopharyngeus muscle, which helps with swallowing. The glossopharyngeal nerve, along with the vagus nerve, forms part of the pharyngeal plexus, which supplies nerves to the palate and parts of the throat (larynx and pharynx).