Multiple sclerosis plaque in the medial longitudinal fasciculus

Case contributed by Dr Chris O'Donnell


Ocular muscle disorder characterized by double vision on lateral gaze. Also dizziness for several weeks.

Patient Data

Age: 40
Gender: Female

Multiple foci of abnormal T2 hyperintensity in subcortical and periventricular white matter, including the calloso-septal interface, right middle cerebellar peduncle and left medial longitudinal fasciculus (MLF) (arrows). Several plaques on the right show restricted diffusion, especially in the peritrigonal white matter, indicating inflammatory activity.

Case Discussion

The medial longitudinal fasciculus (MLF) is a pair of crossed fiber tracts in the midbrain just ventral to the aqueduct containing both ascending and descending fibers. It connects the nuclei of the 3rd, 4th and 6th cranial nerves.

Internuclear ophthalmoplegia is a clinical disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction. It is caused by disruption to the medial longitudinal fasciculus. In young patients demyelination is the commonest cause whereas in older patients, stroke (infarction) is more common.

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Case information

rID: 31882
Published: 3rd Nov 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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