neurologic disorders
Sixth Cranial (Abducens) Nerve Palsy
Symptoms and Signs of Sixth Cranial Nerve Palsy
Symptoms of 6th cranial nerve palsy include binocular horizontal diplopia when looking to the side of the paretic eye. Because the tonic action of the medial rectus muscle is unopposed, the eye is slightly adducted when the patient looks straight ahead. The eye abducts sluggishly, and even when abduction is maximal, the lateral sclera is exposed. With complete paralysis, the eye cannot abduct past midline. Palsy resulting from a cavernous sinus lesion can cause severe head pain, chemosis (conjunctival edema), anesthesia in the distribution of the 1st and 2nd division of the 5th cranial nerve, and paralysis of the 3rd, 4th, and 6th cranial nerves. Both sides may be affected, although unevenly. 