Abducent nerve (VI) lesion - Disorders of cranial nerves

Abducent nerve (VI) lesion

Anatomy

Supplies lateral rectus. It exits from the brainstem and runs through the subarachnoid space into the cavernous sinus, then passes through the superior orbital fissue.

Function

Lateral rectus deviates the eye laterally.

Specific causes

Particularly at risk from raised intracranial pressure or trauma due to its long course. Often occurs as a combined III, IV and VI nerve palsies

Clinical features

Diplopia on looking to the side. III, IV and VI combined nerve palsies are seen in stroke, tumours, Wernicke’s encephalopathy, aneurysms and cavernous sinus thrombosis.