Fig. 15. Electromyography in Duane retraction syndrome. Simultaneous recordings of left lateral rectus (LR) and medial rectus (MR). A. Type I. Peak innervation of lateral rectus on right gaze (paradoxic innervation) and minimal innervation on left gaze. Normal electrical behavior of medial rectus throughout. B. Type II. Lateral rectus innervation on both right and left gaze. Normal electrical behavior of medial rectus throughout. C. Type III. Synchronous and strikingly similar electrical activity in both recti, with intense firing in right gaze (black arrow) and marked inhibition in left gaze (open arrow). (From Huber A: Electrophysiology of the retraction syndromes. Br J Ophthalmol 58:293, 1974)