An AC joint sprain is an injury to the acromioclavicular joint, which is where your collarbone (clavicle) meets the top of your shoulder blade (acromion). This joint helps control shoulder movement and stability. When the ligaments around this joint are stretched or torn, it’s called a sprain. It can range from mild (slight stretch) to severe (complete tear or dislocation of the joint).

An analogy…

Think of the AC joint like a hinge holding up a shelf (your arm). If that hinge is stretched or damaged, the shelf still hangs, but it might wobble or sag, just like your shoulder can feel unstable or painful when the AC joint is sprained.

What are other names that an AC joint sprain can be referred to?

Shoulder Separation, AC Joint Injury, Sprained AC Joint, Torn AC Joint, AC Joint Subluxation, AC Joint Dislocation, Acromioclavicular Joint Injury

What causes an AC joint sprain?

The AC joint is held together by strong ligaments that connect the collarbone to the acromion. A sprain happens when force is placed directly on the shoulder, such as a fall onto the tip of the shoulder, a heavy tackle, or a fall with the arm outstretched. This can stretch or tear the ligaments, causing pain, swelling, and possibly a visible bump where the collarbone sits higher than normal.

What are the signs and symptoms of an AC joint sprain?

• Pain at the top of the shoulder, especially after a fall or impact
• Swelling or bruising over the AC joint
• Pain when lifting the arm, especially overhead or across the body
• A visible lump or bump at the top of the shoulder
• Shoulder weakness or limited range of motion
• In severe cases, the collarbone may appear raised or out of place

What tests are used to diagnose an AC joint sprain?

Cross-Body Adduction Test: This is a physical test used to check for AC joint problems. The practitioner asks you to lift your arm and move it across your body, like you’re reaching toward the opposite shoulder. If this movement causes pain at the top of the shoulder, it suggests irritation or injury to the AC joint.

How long does an AC joint sprain take to heal?

Recovery depends on the severity of the sprain:

• Grade 1 (mild): 1–2 weeks
• Grade 2 (moderate): 3–6 weeks
• Grade 3 (severe): May take 6+ weeks; sometimes surgery is considered

Rest, proper rehab, and protection of the joint are essential during healing.

How does an AC joint sprain happen?

• Falls onto the shoulder or outstretched arm
• Sports involving contact or collisions
• Weak shoulder or upper back muscles
• Poor shoulder mechanics during lifting or throwing

What treatment can help an AC joint sprain?

• Ice packs in the first 48–72 hours
• Sling for support (especially in moderate to severe cases)
• Manual therapy and soft tissue release
• Gradual strengthening and mobility exercises
• Taping or shoulder bracing for protection in early stages
• Return to sport or activity with proper guidance

What exercises or stretches can I do for an AC joint sprain?

• Pendulum swings
• Wall walks
• Scapular setting exercises
• Resistance band shoulder strengthening
• Overhead reaching and functional tasks

What products can help with an AC joint sprain?

• Wheatbag
• Trigger Ball
• KT Pilates Band Pack