brain, spinal cord, and nerve disorders
Third Cranial Nerve (Oculomotor Nerve) Palsy
Introduction
A palsy of the 3rd cranial nerve can impair eye movements, the response of pupils to light, or both. These palsies can occur when pressure is put on the nerve or the nerve does not get enough blood. People have double vision when they look in a certain direction, the eyelid droops, and the pupil may be widened (dilated). Doctors do a neurologic examination and magnetic resonance imaging (MRI) or computed tomography (CT) of the brain. Treatment depends on the cause. (See also Overview of the Cranial Nerves .) Palsy refers to paralysis, which can range from partial to complete. The most common causes of 3rd cranial nerve palsy are Pressure on (compression of) the nerve Inadequate blood flow to the nerve Compressiontends to result from serious disorders, such as A bulge ( Aneurysms of Arteries in the Arms, Legs, and Heart ) in an artery supplying the brain A disorder that causes Herniation: The Brain Under Pressure None Herniation occurs when the brain is forced downward through a small natural opening in the sheets of tissue that separate the brain into compartments. Herniation may result from bleeding (sometimes caused by a Overview of Head Injuries ), a tumor, or another mass in the brain. Inadequate blood flowin very small blood vessels that supply the nerve or in larger ones in the brain stem is more common. It typically results from Diabetes Mellitus (DM) None High Blood Pressure (hypertension) Other disorders that affect blood vessels, such as a Ischemic Stroke , a 