What is a shoulder separation?
A shoulder separation is the partial or complete separation of two parts of the shoulder : the collarbone (clavicle) and the end of the shoulder blade (acromion). See a picture of shoulder separation injuries .
The collarbone and the shoulder blade (scapula) are connected by the acromioclavicular (AC) joint, which is held together primarily by the acromioclavicular (AC) and the coracoclavicular (CC) ligaments. In a shoulder separation (also called an acromioclavicular joint injury), these ligaments are partially or completely torn. A shoulder separation is classified according to how severely these ligaments are injured:
- In a type I injury, the AC ligament is partially torn, but the CC ligament is not injured. See a picture of a type I injury .
- In a type II injury, the AC ligament is completely torn, and the CC ligament is either not injured or partially torn. The collarbone is partially separated from the acromion. See a picture of a type II injury .
- In a type III injury, both the AC and CC ligaments are completely torn. The collarbone and the acromion are completely separated. See a picture of a type III injury .
There are three further classifications, types IV through VI, which are uncommon. These types of shoulder separations may involve tearing of the muscle that covers the upper arm and shoulder joint (deltoid muscle) and the one that extends from the back of the head, neck, and upper back across the back of the shoulder (trapezius muscle).
What causes a shoulder separation?
A direct blow to the top of the shoulder or a fall onto the shoulder, such as a fall from a bicycle, can cause a shoulder separation.
What are the symptoms?
Signs and symptoms of a shoulder separation include:
- Pain at the moment the injury occurs.
- Limited movement in the shoulder area (because of pain, not weakness).
- Swelling and bruising.
- Tenderness over the AC joint on top of the shoulder.
- Possible deformity. The outer end of the collarbone may look out of place, or there may be a bump on top of the shoulder.