Figure 5.

Pathway of the Trochlear Nerve. Elevation and enlargement of the brainstem exposes fibers originating from the trochlear nucleus exiting the dorsal aspect of the midbrain as the Trochlear nerve. This nerve wraps anteriorly and passes between the posterior cerebral artery and superior cerebellar artery along with the oculomotor nerve and continues through the superior orbital fissure to innervate the superior oblique muscle. The dorsal view of the trochlear nerve demonstrates its close proximity to the pineal gland.