vertical muscle of tongue vertical muscle of tongue the vertical muscle of the tongue is an intrinsic muscle of the tongue. its fibers extend from the upper to the under surface of the tongue. it is innervated by the hypoglossal nerve (cranial nerve xii). its contraction flattens, widens and elongates the tongue. vertical muscle of tonguea coronal section of tongue, showing intrinsic muscles.detailsoriginsubmucosal fibrous layer of dorsum of tongueinsertioninferior surface borders of tonguenervehypoglossal nerve (cn xii)actionsflattens and broadens tongueidentifierslatinmusculus verticalis linguaeta98a05.1.04.109ta22125fma46696anatomical terms of muscle anatomy the vertical muscle of the tongue is an intrinsic muscle of the tongue. it is found only at the borders of the forepart of the tongue. structure fibres of the vertical muscle of the tongue are arranged in an almost vertical direction, and intersect the transversely oriented fibres of the transverse muscle of tongue. fibers of the vertical muscle of the tongue extend from the upper to the under surface of the tongue. innervation the vertical of the tongue is innervated by the hypoglossal nerve (cn xii). function contraction of the vertical muscle of the tongue flattens, widens and elongates the tongue.