Cranial Nerves III, IV, and VI

Movements of the eye are produced by six extraocular muscles innervated by three cranial nerves: the oculomotor (III), the trochlear (IV), and the abducens (VI). These cranial nerves are discussed together because of the interrelated nuclear origins, neural pathways, and motor functions. The normal anatomic pathway of these three nerves is presented. The clinical and pathologic manifestations of lesions producing both isolated and complex palsies of these nerves are discussed along with imaging correlation.