Prenuclear paresis of homolateral inferior rectus and contralateral superior oblique eye muscles.
In a case of left inferior rectus paresis, it is demonstrated that the lesion must be prenuclear. On downward gaze, the left eye, although it reached the required target with a rapid saccade, drifted back towards the midline immediately afterwards. During the drift, several corrective saccades appeared. A dissociated "gaze paretic" nystagmus resulted. Synchronously, the right eye showed an incyclorotary nystagmus. We suspect a lesion of "tonic" fibers supplying the nuclear region of the left inferior rectus and the right superior oblique muscle.
D000328:Adult; D005133:Eye Movements; D006801:Humans; D009759:Nystagmus, Pathologic / Q000503:physiopathology; D009801:Oculomotor Muscles / Q000294:innervation / Q000503:physiopathology*; D009886:Ophthalmoplegia / Q000503:physiopathology*