Trochlear nerve

The 4th cranial nerve. The 2 trochlear nerves arise in the brainstem, 1 on each side of the midbrain, and enter the eye sockets through gaps in the skull bones. Each trochlear nerve controls 1 of the 2 superior oblique muscles, which rotate the eyes downwards and outwards.

 

Online Medical Dictionary: Your essential reference to over 5000 medical terms.