Superior Oblique Muscle Layers in Monkeys and Humans

Abstract

The primate SO has a substantial OL configured to contribute to positioning the superior rectus pulley in the coronal plane. Whereas the direction of application of the SO's GL force is determined by the rigid trochlea, the SO's OL influences the direction of application of rectus EOM forces. This insight extends the concept of active control of pulley positions to include a contribution from the SO muscle.