What is an AC Sprain?

AC Joint Sprain

3D Surgical Animation

The shoulder complex is a ball and socket joint and is comprised of 4 main muscles, several bones and several soft tissue structures. The scapula (shoulder blade), clavicle (collar bone), and humerus (upper arm bone) make up the bony components. The upper portion of your shoulder creates a joint between the clavicle and scapula called your AC joint – acromioclavicular.

A separation or sprain of the acromioclavicular joint can be a significant injury. The most common injury to this area is a direct fall onto the top of the shoulder. It can also occur from falling onto an outstretched arm, from a direct blow such as in football tackling. When there is a great enough force to this joint, the ligaments that stabilize it, tear causing a separation. Mild tears are treated conservatively, but significant damage that causes winging or elevation of the joint will require surgery called a weaver-dunn procedure.


Symptoms from the injury will range from mild to severe pending the classification grade. These include decreased shoulder range of motion, shoulder and cervical spasms, swelling, discoloration, tenderness at the injured site and deformity.



Diagnosis will be determined through a thorough history and physical examination by a trained sports medicine and orthopedic shoulder specialist. Examination will consist of palpating the shoulder complex for pain and a visual examination for deformities. The clinician will check bo