AC joint separation

What is an AC joint separation?

The spot where the top of your shoulder blade connects to your collarbone is known as the acromioclavicular joint, or AC joint.

When you have a sprain or a tear of the ligaments that hold the AC joint together, the joint separates. This is also sometimes referred to as a shoulder separation.

An AC joint separation may make your shoulder look deformed.


Symptoms of an AC joint separation may include:

  • Mild to intense pain, depending on how severe the injury is
  • Weakness in the shoulder
  • Bruising or swelling
  • A bump or bulge at the top of the shoulder
  • Reduced range of movement in the shoulder

Causes and risk factors

Most AC joint separations are caused by a fall. Car accidents and participation in contact sports are other common ways an AC joint can become separated.

Treatment options

Nonsurgical treatment includes:

  • Wearing a sling to keep the joint from moving around
  • Putting ice packs on the joint to reduce swelling
  • Non-prescription medicine to reduce the pain

After the pain goes away, exercises can help make your shoulder strong and flexible again.

Surgery may be necessary if the pain lasts a long time or your shoulder appears to be extremely deformed.

Last reviewed: 
June 2017

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