Anatomy of the abducens nerve

The abducens nerve, the sixth cranial nerve, is a paired nerve containing general somatic efferent fibers that innervate the lateral rectus muscle. It originates in the pons, exits the brainstem at the pontomedullary sulcus and via a relatively long intracranial course to the eye where it supplies the ipsilateral lateral rectus muscle for abduction of the eye. Though abducens is a relatively small nerve, it is crucial in assessing the state of health of the brain due to its relatively common demise in a myriad of brain pathologies. The abducens nerve is particularly vulnerable to changes in intracranial pressure. Whereas elevated intracranial pressure may lead to compression of feeding vessels resulting in an ischemic abducens nerve palsy, decreased intracranial pressure poses a risk of a mechanical abducens nerve palsy due to resultant traction of the nerve.