Glossopharngeal nerve

The glossopharyngeal nerve supplies taste to the posterior third of the tongue, parasympathetic fibres to the parotid gland and contributes to the pharyngeal plexus. The motor part of the latter, to the stylopharyngeus, cannot be tested, but the sensory component over the tonsil and anterior pillar of the fauces can by examined by the gag reflex.

The gag reflex is produced by gently touching the anterior pillar with a wooden spatula (figure 38). Taste over the posterior third of the tongue (figure 39), is assessed as with the facial nerve, but this area is more sensitive to bitter tastes, such as quinine.