A 23-year-old male basketball player is admitted to the hospital after injuring his shoulder during a game. Physical and radiographic examinations reveal following injury as noted in x rays ( Fig ). Which of the following structures has most likely been torn?

Acromioclavicular ligament connects the clavicle to the acromion of the scapula. Type I - This is an acute sprain of the acromioclavicular ligaments; the joint is undisplaced. Type II - The acromioclavicular ligaments are torn and the joint is subluxated with slight elevation of the clavicle. * Type III - The acromioclavicular and coracoclavicular ligaments are torn and the joint is dislocated; the clavicle is elevated (or the acromion depressed) creating a visible and palpable 'step' as in this x rays. . Glenohumeral ligament may be injured by an anterior dislocation of the humerus but is not likely to be injured by a separated shoulder. Coracoacromial ligament, transverse scapular ligament, and tendon of the long head of Biceps brachii are not likely to be injured by separation of the shoulder. The weight of the upper limb is transmitted to the axial skeleton by Costoclavicular ligament. Costoclavicular ligament: Transmits weight of the upper limb to the axial skeleton the clavicle. Coracoclavicular ligament: Transmits weight of the upper limb to the clavicle.