Monday, January 31, 2011

Abducens Nerve (CN VI)

The abducens nerve, also known as cranial nerve VI (CN VI), is one of the twelve paired cranial nerves. It is made up of motor axons and innervate the lateral rectus muscle of the eyeball. The CN VI originates in the abducens nucleus which is located in the pons, on the floor of the fourth ventricle. Motor axons leaving the abducens nucleus run ventrally and caudally through the pons, passing lateral to the corticospinal tract, which runs longitudinally through the pons at this level. Then, the abducens nerve leaves the brainstem at the junction of the pons and the medulla, medial to the facial nerve. In order to reach the eye, it runs upward, superiorly, and then bends forward, anteriorly.