AC Joint Dislocation
An acromioclavicular joint separation, or AC separation, is a very frequent injury among physically active people. In this injury the clavicle (collar bone) separates from the scapula (shoulder blade). It is commonly caused by a fall directly on the "point" of the shoulder or a direct blow received in a contact sport. Football players and cyclists who fall over the handlebars are often subject to AC separations.
In general, most AC injuries don't require surgery. There are certain situations, however, in which surgery may be necessary. Most patients recover with full function of the shoulder. The period of disability and discomfort ranges from a few days to 12 weeks depending on the severity of the separation. Disruption of the AC joint results in pain and instability in the entire shoulder and arm. The pain is most severe when the patient attempts overhead movements or tries to sleep on the affected side.
What is an AC joint Dislocation or separation?
The shoulder joint is formed at the junction of three bones: the collarbone (clavicle), the shoulder blade (scapula), and the arm bone (humerus). The scapula and clavicle form the socket of the joint, and thehumerus has a round head that fits within this socket. The end of the scapula is called the acromion, and the joint between this part of the scapula and clavicle is called the acromioclavicular joint. An acromioclavicular joint separation, or AC joint separation or shoulder separation, occurs when the clavicle separates from the scapula. It is commonly caused by a fall directly on the 'point' of the shoulder or by a direct blow received in a contact sport.
What causes an AC joint separation?
A shoulder separation is almost always the result of a sudden, traumatic event that can be attributed to a specific incident or action. The two most common descriptions of a shoulder separation are either a direct blow to the shoulder (often seen in football, rugby, or hockey), or a fall on to an outstretched hand (commonly seen after falling off a bicycle or horse).
What are the typical symptoms of AC joint separation?
- Depending on the grade, a bump may be present on the top of the shoulder where the clavicle ends
- The joint may be very unstable
- Pain and swelling around the joint
- Pain on movement of the arm