Injuries to the clavicle and acromioclavicular joint

The clavicle is a doubly-curved long bone which acts as the only osseous strut connecting the trunk to the shoulder and arm (Figure 1). Medially the clavicle articulates with the manubrium of the sternum at the sternoclavicular joint, while laterally it articulates with the acromion of the scapula at the acromioclavicular joint. Trapezius and deltoid muscles attach to the flat outer third, as do the acromioclavicular and coracoclavicular ligaments. The tubular medial third is a boundary of the cervicoaxillary canal, and as such affords protection to the neurovascular bundle supplying the upper limb, including the brachial plexus, subclavian and axillary vessels. The junction between these two different crosssectional configurations occurs in the middle third, which constitutes an area vulnerable to injury.