Cranial nerve III, the oculomotor nerve, arises from the mid-brain and passes into the orbits of the eyes. One part of each oculomotor nerve connects several voluntary muscles: the levator palpebrae superioris muscles, which raise the eyelids, and most of the muscles attached to eye surfaces that cause them to move - the superior rectus, medial rectus, and inferior oblique muscles. The second part of the nerve supplies involuntary muscles inside the eyes. These act to adjust the amount of light that enters the eyes and aid in focusing the lenses of the eyes. They are number III in the cranial nerve order from the front of the brain. They also contain some sensory nerve fibers to transmit information about the condition of certain eye muscles.