Cardinal Positions of Gaze

The cardinal positions of gaze are possible due to the extra ocular muscles. These, muscles are extremely strong and efficient. There are six extra ocular muscles which are responsible for turning or rotating the eye horizontally, vertically and in antero-posterior axes

An extra ocular muscle helps the pupil in front of the eye to move in a specific direction:

Lateral rectus (LR): moves the eye in the outward direction away from the nose

Medial rectus (MR): moves the eye in the inward direction, toward the nose

Inferior rectus (IR): Primarily moves the eye in the downward direction. Secondarily rotates the top portion of the eye away from the nose and tertiary job is to move the eye inward.

Superior rectus (SR): Primarily moves the eye in the upward direction. Secondarily rotates the top portion of the eye toward the nose and the tertiary job is to move the eye inward.

Inferior oblique (IO): Primarily rotates the top portion of the eye away from the nose. Its second task is to move the eye upward and the third task is to move the eye outward.

Superior oblique (SO): Primarily rotates the top portion of the eye toward the nose. Its second task is to move the eye downward and the third task is to move the eye outward.