Superior Oblique Myokymia - Causes

Causes

In 1983, Bringewald postulated that superior oblique myokymia resulted from vascular compression of the trochlear nerve (fourth cranial nerve), which controls the action of the superior oblique muscle in the eye. By 1998, there had been only one reported case of compression of the trochlear nerve by vessels. More recently, magnetic resonance imaging experiments have shown that neurovascular compression at the root exit zone of the trochlear nerve can result in superior oblique myokymia.