Vagus nerve, cranial nerve X is the longest cranial nerve which runs from the brain through the face and thorax to the abdomen. It is a mixed nerve that contains parasympathetic fibres. Related Theory The Hypoglossal Nerve (Cranial Nerve XII) is mainly an efferent nerve for the tongue musculature. There are two cranial nerves that innervate the tongue and are used for taste: the facial nerve (cranial nerve VII) and the glossopharyngeal nerve (cranial nerve IX ). Caution Mnemonics - SAME : Sensory nerve Afferent nerves; Motor nerves Efferent nerves