Shoulder Joint

The humerus, scapula, & clavicle together makeup the shoulder girdle. The clavicle attaches to the sternum in the front body via a small disc of cartilage (referred to as the sternoclavicular joint). The clavicle is able to elevate, depress, protract, retract, & rotate. We experience downward & forward rotation of the clavicle in reverse prayer position. The other end of the clavicle attaches to the scapula (shoulder blade) & is bound together by several ligaments at the acromion process. This is the acromioclavicular (AC) joint & is the small bump we can palpate on top of the shoulder. The acromion is a small ledge of the scapula that sits on top of the humerus. At the top of the lateral edge of the scapula & just underneath the acromion process is a deep depression in the bone. This is referred to as the glenoid fossa & is where the head of the humerus sits (also referred to as the shoulder joint or glenohumeral joint). The scapula sits at about a 45 degree angle relative to the body. As the scapula is connected to the humerus, this creates a mirrored 45 degree angle from which the humerus is oriented to the body. Movements of the shoulder joint include flexion (arms overhead), extension (arms behind), abduction, adduction, & medial & lateral rotation. Once the humerus reaches the end of its range of motion (ROM), it will hit the acromion & begin to move the scapula as well.