Which AC joint sprain type involves tears of both the AC and CC ligaments with distal clavicle unstable and elevated?

Which AC joint sprain type involves tears of both the AC and CC ligaments with distal clavicle unstable and elevated?

• A. Type 2
• B. Type 3
• C. Type 4
• D. Type 5

Answer: (B)

Stability of the AC joint depends on two ligaments: the acromioclavicular ligaments across the joint and the coracoclavicular ligaments that suspend the clavicle from the coracoid. When both sets are torn, the distal clavicle loses restraint in both directions, becoming unstable and riding upward relative to the acromion. This combination—tears of both AC and CC ligaments with the distal clavicle clearly elevated— defines that injury pattern. Other patterns involve only one ligament torn or different directions of displacement, so they don’t match the description of both ligaments torn with elevation. Thus, the described injury corresponds to the type where both AC and CC ligaments are torn and the distal clavicle is elevated.

Stability of the AC joint depends on two ligaments: the acromioclavicular ligaments across the joint and the coracoclavicular ligaments that suspend the clavicle from the coracoid. When both sets are torn, the distal clavicle loses restraint in both directions, becoming unstable and riding upward relative to the acromion. This combination—tears of both AC and CC ligaments with the distal clavicle clearly elevated— defines that injury pattern. Other patterns involve only one ligament torn or different directions of displacement, so they don’t match the description of both ligaments torn with elevation. Thus, the described injury corresponds to the type where both AC and CC ligaments are torn and the distal clavicle is elevated.