Let's Talk About ... The Acromioclavicular Joint

By Ben Benjamin, PhD

Question: Where do acromioclavicular (AC) joint or ligament sprains generally cause pain?

Answer: Right where the injury is located, at the joint formed by the acromion portion of the scapula and the distal end of the clavicle.

Unlike many other shoulder injuries, sprains of the AC joint or ligament typically cause little or no referred pain.

Question: What is the most painful test when the acromioclavicular ligament or joint is sprained?

Answer: Passive horizontal adduction.

In cases of AC joint or ligament sprain, most or all passive tests of the shoulder are painful at the end of the range of movement. At the end of those movements, there is a pull on the acromioclavicular joint, causing pain or discomfort. Passive horizontal adduction is the most painful because as the arm is horizontally adducted, the upper arm muscles place stress on the bones of the AC joint. The client feels significant pain immediately when this test is initiated.

Question: Is hands-on therapy an appropriate treatment for this type of injury?

Answer: When the ligament is injured, manual treatment usually is quite effective. When the joint is injured, manual therapy is not effective.