trochlear nerve The fourth cranial nerve. Each of the two trochlear nerves controls one of the small muscles (ocular muscles) which moves each eyeball, and is purely motor. Like the oculomotor nerve, the trochlear nerves arise in the brainstem, one on each side of the midbrain. They enter the eye sockets through gaps in the skull bones. Related category • ANATOMY AND PHYSIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |