The
glossopharyngeal nerve, known as the ninth
cranial nerve (CN IX), is a mixed nerve that carries afferent sensory and efferent motor information. It exits the brainstem out from the sides of the upper
medulla, just rostral (closer to the nose) to the
vagus nerve. The motor division of the glossopharyngeal nerve is derived from the
basal plate of the
embryonic medulla oblongata, while the sensory division originates from the
cranial neural crest.