Palsies of the third, fourth, and sixth cranial nerves

Diplopia is one of the most vexing problems to confront a physician. When diplopia is binocular, it commonly results from dysfunction of one or more of the ocular motor nerves. Ocular motor dysfunction may result from injury anywhere along the neuraxis, from the ocular motor nucleus to the myoneural junction. Identifying the location of the lesion is important for determining the etiology and prognosis of third-, fourth-, and sixth-nerve injuries. In this article, an anatomic approach is presented for the diagnosis and treatment of ocular motor nerve lesions. Emphasis is placed on the identification of associated neurologic and ophthalmologic findings that are critical for management of patients with acquired and congenital ocular motor palsies.