Cranial Nerve III, IV and VI

Internuclear ophthalmoplegia

Overview

• a cause of horizontal disconjugate eye movement
• due to a lesion in the medial longitudinal fasciculus (MLF)
  • controls horizontal eye movements by interconnecting the IIIrd, IVth and VIth cranial nuclei
  • located in the paramedian area of the midbrain and pons

Features

• impaired adduction of the eye on the same side as the lesion
• horizontal nystagmus of the abducting eye on the contralateral side

Causes

• multiple sclerosis
• vascular disease