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.
How is a shoulder separation diagnosed?
A shoulder separation is diagnosed through a medical history, a physical exam, and an X-ray.
Your doctor will check:
For a deformity or bump.
The range of motion of your shoulder and other joints.
Blood flow, by taking your pulse and assessing your skin color and temperature.
Your doctor will probably X-ray your injured shoulder and possibly your uninjured shoulder to help diagnose the severity of the separation.
How is it treated?
Treatment of a shoulder separation depends on its severity. For a type I or II injury, you support your shoulder with a sling. You typically need the sling until the discomfort decreases (a few days to a week). Early physical therapy to strengthen your shoulder and regain range of motion is important for recovery and to prevent frozen shoulder, a condition that limits shoulder motion (adhesive capsulitis). You can return to normal exercises and activities as your pain and other symptoms go away.
Experts don't agree on the best treatment for type III injuries. Some doctors treat them with a sling and physical therapy, while others feel surgery may be needed.
Type IV through VI injuries should be evaluated for possible surgery.
To help relieve pain, put ice on the affected area and take nonsteroidal anti-inflammatory drugs, such as ibuprofen or naproxen. Be safe with medicines. Read and follow all instructions on the label.
American Academy of Orthopaedic Surgeons and American Academy of Pediatrics (2010). Acromioclavicular injuries. In JF Sarwark, ed., Essentials of Musculoskeletal Care, 4th ed., pp. 263â€“268. Rosemont, IL: American Academy of Orthopaedic Surgeons.
McMahon PJ, et al. (2014). Sports medicine. In HB Skinner, PJ McMahon, eds., Current Diagnosis and Treatment in Orthopedics, 5th ed., pp. 88â€“155. New York: McGraw-Hill.
ByHealthwise StaffPrimary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency MedicineAdam Husney, MD - Family MedicineKathleen Romito, MD - Family MedicineSpecialist Medical ReviewerPatrick J. McMahon, MD - Orthopedic Surgery, Sports Medicine