Anatomy of the Scapula

Abstract

Ideal scapular function reflects its complex anatomy and in turn is foundational for all shoulder function. The scapula plays a multitude of roles. Anatomically, it is the “G” of the glenohumeral (GH) joint and the “A” of the acromioclavicular (AC) joint. Physiologically, it is the “S” of scapulohumeral rhythm (SHR), the coupled and coordinated movement between the scapula and arm that allows the arm to be placed in the optimum position and motion to accomplish tasks. Biomechanically, it provides a stable base for muscle activation, a moving platform to maintain ball-and-socket kinematics, and an efficient link between the core, which develops force, and the arm, which delivers the force. Critical to these roles is normal scapular motion.