Anatomy of sensory component

The sensory component of the vagus nerve consists of two key functional divisions.

General sensation from the external ear passes via the auricular branch of the vagus nerve through the petrous portion of the temporal bone. From here it passes through the superior vagal ganglion and thence the jugular foramen before entering the medulla to terminate in the spinal trigeminal nucleus.

General visceral afferent fibres originate in the walls of various tracts and convey, for example, information about pressure and volume. Fibres from the oesophagus form the oesophageal plexus, and there are similar plexuses for the heart and lungs. These merge on the vagal nerve proper as it ascends in the carotid sheath as a continuation of the vagal trunks formed from abdominal plexuses.

Afferent fibres from the larynx and pharynx - including taste fibres from the tongue and epiglottis - join the vagus nerve at the angle of the mandible before passing upwards as a vagal rootlet to the brainstem. All of the general visceral afferent fibres contribute to the tract of the nucleus solitarius - this has intimate association with the reticular formation and medullary cardiovascular and respiratory centres.