Trochlear nerve
(B) Is the only cranial nerve to emerge from the dorsal aspect of the brainstem # TROCHLEAR NERVE emerges from the superior medullary velum near the frenulum veli just below the inferior colliculus.> Trochlear nerve is the only cranial nerve which emerges on the dorsal aspect of the brainstem.> When the trochlear nerve is damaged, diplopia occurs on looking downwards: vision is single so long as the eyes look above the horizontal plane.
Supplies the inferior oblique muscle of the eyeball
Is the only cranial nerve to emerge from the dorsal aspect of the brainstem
Has its nucleus of origin in the midbrain at the level of the superior colliculus
Enters the orbit through the middle compartment of the superior orbital fissure
Neuroanatomy