Abducens nerve (CN VI)

  • The abducens nerve (sixth cranial nerve, CN VI, latin: nervus abducens) is a motor nerve that carries general somatic efferent fibers to exclusively innervate the lateral rectus muscle of the eye.

    The abducens nerve arises from neuronal cell bodies originating in the abducens nucleus, which is located in the dorsal pons, in the floor of the fourth ventricle.

    The sixth cranial nerve emerges from the brainstem at the caudal border of the pons in the pontomedullary junction, generally, in line with the rootlets of the hypoglossal nerve (CN XII). The abducens nerve then pierces through the dura mater covering the clivus, runs upward in the Dorello canal between the dura and the skull, then bends sharply across the upper border of the petrous part of the temporal bone, and enters the cavernous sinus. The abducens nerve is the only cranial nerve traversing the cavernous sinus. Within the cavernous sinus the abducens nerve lies just inferolateral to the internal carotid artery. After passing the sinus the nerve enters the orbit through the superior orbital fissure within the common tendinous ring (annulus of Zinn). The abducens nerve then passes forward to innervate the lateral rectus muscle at the surface of the eye orbit.