anatomy of the sensory component

Last reviewed 01/2018

The sensory branch of the glossopharyngeal nerve arise from several sites. Afferent general sensory neurones from the palate and pharynx mucosae join the pharyngeal branch of the glossopharyngeal nerve; the tonsillar branch originates from all of the tonsils.

General sensory neurones from the skin of the external auditory meatus and the back of the ear pass with the facial nerve or the auricular branch of the vagus nerve. The latter join the glossopharyngeal nerve in the jugular foramen. Ultimately, signals are passed to the spinal nucleus of the trigeminal nerve.

Afferent neural signals from the carotid sinus and carotid body are conveyed via the sinus nerve division of the glossopharyngeal nerve.

Taste receptors on the posterior third of the tongue - behind the sulcus terminalis - are contacted by fibres from the lingual branches of the glossopharyngeal nerve. These pass upwards between the internal and external carotid arteries to form, with other branches of the glossopharyngeal nerve, the inferior ganglion at the entrance to the jugular foramen.

Gustatory fibres join fibres from cranial nerves VII, IX and X to synapse with the nucleus solitarius. Baroreceptor fibres terminate in the dorsal motor nucleus of the vagus nerve.