Acromioclavicular Joint Injury

Also known as shoulder separation, an acromioclavicular joint injury occurs at the top of the shoulder where the clavicle meets the acromion (in the shoulder blade). There are three important ligaments supporting the joint, and damage to these can lead to separation of the bones in the joint.


The primary symptom is pain particular to the joint, over the extremity of the collar bone, though you may initially experience pain in the whole shoulder area. The pain will also be present when you move the shoulder, and lifting the affected arm is likely to be considerably painful. This is regularly accompanied by inflammation or swelling, and in severe cases you might be able to identify a bump at the site of shoulder separation.

Grades of Injury

The severity of the injury may be graded from 1 to 6. Grade 1 involves a strain or small tear to the acromioclavicular ligaments (AC), and is relatively minor, usually healing in days or weeks. In Grade 2 injuries a full rupture of the AC ligaments occurs, in addition to a smaller tear or sprain in the coracoclavicular ligaments (CC). Both the AC and CC ligaments suffer significant tears in a Grade 3 injury, and can take a number of weeks or months to recover.

Grades 4, 5 and 6 go beyond these serious ruptures and the grading is concerned with the severity of shoulder displacement. These injuries will often require surgery.


Injuries of this kind are mostly related to an abrupt event like a fall or another strike to the shoulder, sometimes involving hyperextension of the joint beyond its limits. In sport this can result from a violent blow during contact sports like rugby, ice hockey or football, or a fall from a horse or bicycle.

Medical Attention

Consult a medical professional who will diagnose the injury and may place the shoulder in a sling to prevent unnecessary motion or strain. This may also be essential in letting the joint heal in the correct position. They can also prescribe anti-inflammatory medication if required, and provide support and advice for rehabilitation. If your injury falls in Grades 4 to 6 then it is likely they will recommend surgery.


It is crucial to rest the joint properly; this means ceasing all sports and activities that could place strain on the shoulder, possibly including a temporary alteration of minor actions like your sleeping position and reaching for objects. You should ice the joint, and also maintain the shoulder's mobility when the pain has lessened, undertaking relevant gentle stretches and strengthening exercises to increase flexibility. A doctor or physical therapist will be able to help in constructing a suitable program; however you should cease these exercises and seek additional medical treatment if during them you feel sharp pain.


Regular stretching and strengthening of the shoulder muscles will help to keep this injury at bay. It is also important to return to full activity only at the right time, when you have recovered full strength and motion in your arm, and to be careful with the amount of strain placed upon the shoulder.

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