This summary of the superior oblique muscle describes its most important functions. However, it is an oversimplification of the actual situation. For example, the tendon of the superior oblique inserts "behind" the equator of the eyeball in the frontal plane, so contraction of the muscle also tends to "abduct" the eyeball (turn it outward). In fact, each of the six extraocular muscles exerts rotational forces in "all three planes" (elevation-depression, adduction-abduction, intorsion-extorsion) to varying degrees, depending on which way the eye is looking. The relative forces change every time the eyeball moves—every time the direction of gaze changes. The central control of this process, which involves the continuous, precise adjustment of forces on twelve different tendons in order to point both eyes in exactly the same direction, is truly remarkable.