Neurologic examination reveals bilateral medial rectus paresis on attempted lateral gaze, monocular horizontal nystagmus in the abducting eye, and unimpaired convergence. The lesion is in the:
High-Yield Explanation
Pt is having B/L internuclear Ophthalmoplegia (BINO) d/t involvement of B/L Medial longitudinal fasiculus (MLF), which is located in the dorsomedial midpontine tegmentum. It connects the cranial nerve nuclei III, IV and VI and integrates movements directed by the gaze centers and information about head movement. MLF syndrome is frequently seen in multiple sclerosis and less often in vascular lesions.