AC Joint Pain (Sprain / Separated Shoulder): Symptoms, Causes & PT Treatment
Updated July 20261 minute read
The AC (acromioclavicular) joint sits right on top of your shoulder where the collarbone meets the shoulder blade. A sprain — often called a "separated shoulder" — usually follows a fall onto the shoulder and causes pinpoint pain on top, worse when reaching across your body. Most low-grade sprains heal well with physical therapy; higher-grade or deformed injuries need medical evaluation.
What is an AC joint sprain?
It's an injury to the ligaments supporting the small joint on top of the shoulder. Sprains are graded by severity, from mild stretching to a visible step-off ("separation").
Symptoms
Pain and tenderness right on top of the shoulder, worse with reaching across the body, lifting, or sleeping on that side. A higher-grade injury may show a bump where the collarbone end lifts up.
What causes it / risk factors
A direct fall onto the shoulder or onto an outstretched hand is the usual cause — common in cycling, contact sports, and slips.
How it's diagnosed
A clinician localizes the pain to the AC joint and grades it; X-ray helps assess higher-grade injuries.
Physical therapy treatment
What a PT does. Your therapist controls early pain, restores motion, and strengthens the shoulder-blade and cuff muscles to support the joint. Exercises & progression (overview). Early gentle motion, then scapular and cuff strengthening and graded return to lifting and overhead tasks. Recovery timeline. Low-grade sprains often improve within a few weeks; higher grades take longer.
Treatment options compared
Most low-to-moderate sprains are managed with PT. Surgery is reserved for severe separations or persistent problems.
Red flags
Seek prompt care for an obvious deformity or step-off after a fall, inability to move the arm, or arm pain with chest symptoms (emergency).
Frequently asked questions
Sources (3)
- AAOS OrthoInfo: Shoulder Separation. — AAOS OrthoInfo
- MedlinePlus: Shoulder Injuries and Disorders. — NIH/MedlinePlus
- MedlinePlus Medical Encyclopedia: Shoulder pain. — NIH/MedlinePlus
This article is for education only and isn't medical advice. Always talk to a licensed clinician about your specific situation.