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Third nerve palsy
Other Resources UpToDate PubMed

Third nerve palsy

Contributors: Carolyn Zyloney MD, Richard L. Barbano MD, PhD
Other Resources UpToDate PubMed


Palsy, or paralysis, of the third cranial nerve (oculomotor nerve) usually presents with weakness or paralysis of the extraocular muscles and ptosis in 1 eye. The patient may experience this as diplopia, or double vision. There may be associated headache or ocular pain.

The annual incidence of third nerve palsy is estimated at approximately 4 per 100 000. It is most common in people over age 60. Infarction of the third cranial nerve is the most common cause and often occurs in patients with diabetes, hypertension, or atherosclerosis.

Palsy from infarction presents more acutely. Patients with ischemic third nerve palsies usually do not have pupillary dysfunction. In 20% of patients, the third nerve palsy is due to compression of the oculomotor nerve by tumors (eg, meningioma), herniation, or a brain aneurysm. If nerve dysfunction is caused by external compression (eg, from a tumor), pupil dilation may also occur due to the peripheral location of these nerve fibers. If the third nerve palsy is caused by compression from a tumor, symptoms are usually subacute in onset and gradually progressive. Other common causes include trauma and neurosurgical procedures.

Treatment is primarily aimed at the underlying cause. Most patients with a third nerve palsy require emergent evaluation and neuroimaging to evaluate for compressive lesions, including aneurysms.


H49.00 – Third [oculomotor] nerve plasy, unspecified eye

388980004 – Third cranial nerve weakness

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Differential Diagnosis & Pitfalls

  • Internuclear ophthalmoplegia
  • Myasthenia gravis
  • Thyroid ophthalmopathy (see Graves ophthalmopathy)
  • Strabismus
  • Migraine headache
  • Acute inflammatory demyelinating polyneuropathy
  • Bacterial meningitis
  • Carotid-cavernous fistula
  • Dural arteriovenous malformations
  • Cavernous sinus thrombosis
  • Cerebral aneurysm
  • Cerebral stroke
  • Ophthalmoplegic Migraine headache
  • Tolosa-Hunt syndrome
  • Pituitary apoplexy
  • Giant cell arteritis
  • Orbital trauma
  • Nonspecific orbital inflammation
  • Herpes zoster

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Last Reviewed:12/11/2018
Last Updated:08/31/2023
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Third nerve palsy
Clinical image of Third nerve palsy - imageId=3524543. Click to open in gallery.  caption: 'Eyelid ptosis.'
Eyelid ptosis.
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