Introduction to Anatomy and Neural Pathways

Abstract

This review of the anatomy and neural pathways of motility has focused on the supranuclear pathways for eye movement, because these are the pathways that are responsible for misalignments that are often unfamiliar to the ophthalmologist. In these cases, the pattern of ocular misalignment does not seem to fit a cranial nerve palsy nor seem attributable to myasthenia gravis or orbital causes. When the motility pattern on exam does not seem to fit the distribution of the third, fourth, or sixth cranial nerve, myasthenia, or orbital causes, then supranuclear disorders of gaze should be considered. The most common supranuclear disorders encountered are internuclear ophthalmoplegia, skew deviation, dissociated vertical deviation (DVD), dorsal midbrain syndrome, and horizontal and vertical gaze palsies. The motility examination with prism measurements in different gaze positions in conjunction with neuroimaging usually points the diagnosis toward a supranuclear cause.