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What is AC Joint Separation?

AC joint separation, also known as shoulder separation, is a condition characterized by damage to the ligaments that connect the acromion to the collar bone. As a result, the bones do not line up properly, causing joint pain and instability.

Picture of AC Joint Separation

Causes of AC Joint Separation

Causes include:

  • A fall on the shoulder
  • Lifting heavy objects
  • A sports injury
  • Repetitive overhead activity 

Symptoms of AC Joint Separation

Symptoms include:

  • Pain
  • Weakness in the arm or shoulder
  • Loss of motion
  • Swelling
  • Bruising

Diagnosis of AC Joint Separation

Diagnosis can be made based on discussion of your symptoms and a physical examination of the shoulder. A shoulder X-ray may be ordered to confirm the diagnosis of AC joint separation.

Treatment for AC Joint Separation

Conservative treatment is usually effective, but in cases of a severely unstable joint, surgery is required. The treatment methods include:

Conservative method:

  • Medications: You will be provided with anti-inflammatory pain medications to reduce swelling.
  • Rest: You will be instructed to avoid activities that provoke pain and to make use of a sling to immobilize your shoulder and arm.
  • Ice: An ice pack can be applied for 15-20 minutes at a time to reduce swelling and pain.
  • Physical therapy: Specific exercises can be done to help strengthen the shoulder muscles.


Your doctor will make small incisions through which specialized instruments can be inserted to repair and reattach torn ligaments and stabilize the bones.