
Acromioclavicular joint separation, also known as AC separation, is an injury to the acromioclavicular joint, which is the joint where the collarbone (clavicle) meets the shoulder blade (scapula). It occurs when the ligaments that hold the joint together are torn or stretched.
The acromioclavicular joint is a small joint that helps to stabilize the shoulder joint. It is made up of two bones: the clavicle and the scapula. The ligaments in the joint help to keep the bones in place and prevent them from moving too much.
AC separation can be caused by a fall or a direct blow to the shoulder. It is most common in contact sports, such as football and rugby.

There are three grades of AC joint injuries:
- Grade 1: The ligaments are stretched but not torn.
- Grade 2: The ligaments are torn but the bones do not move out of place.
- Grade 3: The ligaments are torn and the bones move out of place.
Symptoms of AC separation
Symptoms of AC separation can vary depending on the severity of the injury. Common symptoms include:
- Pain in the front, side, or back of the shoulder
- Bruising around the shoulder
- Swelling in the shoulder
- Decreased range of motion in the shoulder
- A lump or bump in the front of the shoulder
The diagnosis of AC separation is made by a doctor based on your medical history, physical examination, and imaging tests, such as an X-ray or MRI.
The treatment for AC separation depends on the severity of the injury.
Mild cases (grade 1) may be treated with rest, ice, and over-the-counter pain medication. More severe cases (grades 2 and 3) may require physical therapy, corticosteroid injections, or surgery.
Physical therapy can help to strengthen the muscles around the shoulder and improve range of motion. Corticosteroid injections can help to reduce inflammation and pain. Surgery is only used in severe cases when other treatments have not been successful.
The prognosis for AC separation is usually good. Most people make a full recovery with time and treatment.
If you have any pain in your shoulder, we encourage you to make an appointment to see the doctors at Warrandyte Road Clinic to get a diagnosis and treatment.