The scapula (shoulder blade) is an oddly shaped bone, with many projections that form either joints or key tendon attachment points that enable high mobility without compromising stability of the shoulder.

The proximal humerus articulates with the scapula at the glenoid projection to form the main shoulder joint. Above this is the acromioclavicular joint, that joins the clavicle to the scapula. The coracoid is slightly below and medial to this, and is the primary projection from which three tendons originate or insert.

In order for the shoulder to move properly, there needs to be both slide of the scapula body over the chest wall, and movement in the glenohumeral joint in order for our arms to get above our heads.

Trauma to the shoulder may cause fractures in any of the clavicle, the scapula, including the glenoid, coracoid and acromial projections, and the proximal humerus. Older patients with more brittle bones get proximal humerus fractures and younger patients more commonly have clavicle fractures. The force of the injury may cause multiple injuries and it is important to recognize these and be able to appropriately assess their contribution to shoulder function, as this determines whether they might be more appropriately be managed operatively or non-operatively.

For instance, in the case of proximal humerus fractures in older patients, if the humeral head is significantly injured, fixation and healing of the head fragments are unpredictable. In such a case it is important that the surgeon be able to perform a reverse total shoulder arthroplasty, as the outcomes in this group of patients are far better.