Oculomotor nerve palsy

Oculomotor nerve palsies, or third nerve palsies, result in weakness of the muscles supplied by the oculomotor nerve, namely the superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae superioris muscles.

Classically, patients present with diplopia and physical exam findings ipsilateral to the oculomotor nerve (CN III) lesion:

  • "down and out" ocular positioning
    • abduction, slight depression, and intorsion (due to paralysis of adduction, elevation, and depression)
  • complete ptosis
  • +/- enlarged unreactive pupil
    • suggests compression of CN III, because the parasympathetic pupillary fibers are located peripherally in the nerve and more likely affected from external compression

It has numerous possible etiologies which can be divided according to which portion of the nerve is affected:

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Article information

rID: 1761
Synonyms or Alternate Spellings:
  • Third nerve palsy
  • Third cranial nerve palsy

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Cases and figures

  • Case 1: with eye down and out
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  • Case 2: oculomotor schwannoma
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  • Case 3: infarction of oculomotor nucleus
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