Yoke muscle pair

Yoke muscles are the primary muscles in each eye that accomplish a given version (eg, for right gaze, the right lateral rectus and left medial rectus muscles). Each extraocular muscle has a yoke muscle in the opposite eye to accomplish versions into each gaze position. By the Herring law, yoke muscles receive equal and simultaneous innervation. The magnitude of innervation is determined by the fixating eye, which means that the angle of detion between eyes (strabismus) may vary depending on which eye is fixating. The primary detion is misalignment, with the normal eye fixating. If the paretic eye fixates, the ensuing secondary detion is typically larger than the primary detion. Ref - medscape.com