Complete Calisthenics - Ashley Kalym

There are six primary directions of scapular movement: elevation, depression,
upward and downward rotation, and protraction and retraction. Elevation
occurs when you shrug your shoulders up, or move your shoulders to your ears.
Depression occurs when you let your shoulders sink down toward the ground.
Upward rotation occurs as you reach the arm overhead and the glenoid cavity
faces up toward the sky, while downward rotation occurs as you bring your arm
back from the overhead position. Retraction occurs when you adduct and pull
your shoulders back while lifting your chest up, and protraction occurs as you
reach your arms forward and pull your shoulder blades away from the spine.
The scapula is also an important muscular attachment point for the muscles of
the glenohumeral (ball-and-socket) joint, including the deltoid and rotator cuff.
The glenohumeral joint has been analogously described as a golf ball sitting on a
tee. The rotator-cuff muscles are therefore particularly important in maintaining
glenohumeral joint stability through a wide range of activities.