Classification Description Notes
Type 1 AC Joint strain Normal radiograph
Type 2 AC disrupted, CC strain Mild vertical separation (normal AC interval 5-8 mm)
Type 3 AC and CC disrupted CC distance 25-100% of contralateral side
Type 4 Distal clavicle positioned posterior to acromion
Type 5 Subcutaneous distal clavicle CC distance >100% contralateral side
Type 6 Distal clavicle positioned inferior to coracoid Rare: Deep to conjoined tendon (coracobracialis, short head biceps)



Gorbaty, J. D., et al. (2017). “Classifications in Brief: Rockwood Classification of Acromioclavicular Joint Separations.” Clinical Orthopaedics and Related Research® 475(1): 283-287.

Rockwood CA Jr. Fractures and dislocations of the shoulder. In: Rockwood CA Jr, Green DP, eds. Fractures in Adults. Philadelphia, PA: Lippincott; 1984:860–910.