A separated shoulder is an injury to the joint where your collarbone meets the top of your shoulder blade. Despite the name, the bone doesn’t actually “separate” from your body. Instead, the ligaments holding these two bones together get stretched or torn, allowing them to shift apart. It’s one of the most common shoulder injuries, especially in contact sports and falls, and it ranges from a mild sprain that heals in a couple of weeks to a severe tear that may need surgery.
The Joint Involved
The injury happens at the acromioclavicular (AC) joint, a small connection point at the very top of your shoulder. Here, the outer end of your collarbone meets a bony projection on your shoulder blade called the acromion. Three ligaments hold these bones together and keep the joint stable. When force drives the shoulder downward or inward, those ligaments can stretch, partially tear, or rupture completely.
The most common cause is a direct blow to the top or side of the shoulder, the kind that happens when a football player gets tackled, a cyclist goes over the handlebars, or someone falls hard onto the point of the shoulder. Less often, falling on an outstretched hand can transmit enough force upward to damage the joint.
It’s Not the Same as a Dislocated Shoulder
People often confuse these two injuries, but they involve completely different joints. A separated shoulder affects the AC joint at the top of the shoulder, where the collarbone meets the shoulder blade. A dislocated shoulder happens at the ball-and-socket joint lower down, where the upper arm bone pops out of its cup-shaped socket on the shoulder blade. The pain location, the visible deformity, and the treatment approach are all different.
What It Feels and Looks Like
The hallmark symptom is sharp pain right at the top of your shoulder, directly over the AC joint. Swelling, tenderness, and bruising typically appear quickly after the injury. You’ll likely have difficulty lifting your arm or moving it through its normal range, especially reaching across your body or overhead.
In more severe separations, you may notice a visible bump on top of your shoulder. This happens because the torn ligaments let your shoulder blade sag downward under the weight of your arm, pushing the end of your collarbone upward. That bump, sometimes called a “step-off” deformity, can be subtle or quite prominent depending on the severity. In the most severe cases, the displaced collarbone can tent the skin or push backward into the muscle behind it.
The Six Grades of Severity
Doctors classify AC joint separations into six types, based on how much the ligaments are damaged and how far the bones have shifted apart.
- Type I: The ligaments are stretched but not torn. X-rays look normal, and the joint is still stable. This is essentially a sprain.
- Type II: The main AC ligament is torn, and a second set of ligaments below (connecting the collarbone to another part of the shoulder blade) is stretched. The joint shows some looseness, and X-rays reveal a slight widening.
- Type III: Both sets of ligaments are torn. The collarbone visibly shifts upward, and X-rays show a noticeable gap between the bones.
- Type IV: Both ligament groups are torn, and the end of the collarbone is displaced backward into the trapezius muscle. This often creates visible fullness behind the shoulder.
- Type V: A more extreme version of Type III, with the collarbone displaced dramatically upward. The shoulder droops severely and doesn’t improve when you try to shrug.
- Type VI: The rarest form. The collarbone is driven downward beneath the shoulder blade, usually from high-energy trauma. This type often comes with other injuries.
How It’s Diagnosed
A physical exam often gives a strong indication, especially when there’s a visible bump and point tenderness at the AC joint. X-rays confirm the diagnosis and determine the grade. Standard front-to-back views show the joint alignment, and a specialized angle called the Zanca view tilts the X-ray beam 10 to 15 degrees upward to get a clearer picture of the AC joint without the overlapping bones that can obscure it on regular films. Sometimes both shoulders are X-rayed for comparison, since doctors measure how much the gap between the bones has widened relative to the uninjured side.
Treatment by Grade
Types I and II are almost always treated without surgery. The standard approach is a sling to immobilize the shoulder, ice, and pain management. For a Type I sprain, immobilization typically lasts 7 to 10 days. Type II injuries generally need the sling for 4 to 6 weeks as the partially torn ligaments heal.
Type III is the gray area. This grade has been debated for decades, and a large review of randomized trials found no clear advantage of surgery over conservative treatment for Type III separations when it comes to functional outcomes or complication rates. Some specialists now subdivide Type III into a stable version and an unstable version, using the stability of the joint to guide the decision. For younger athletes or people with physically demanding jobs, the conversation about surgery may lean differently, but many Type III injuries do well with rehab alone.
Types IV, V, and VI generally require surgical repair because the collarbone is too far out of position for the ligaments to heal on their own.
Rehabilitation and Recovery Timeline
For non-surgical cases, rehab follows a gradual progression. After the initial period in a sling, you move into gentle passive and active range-of-motion exercises to prevent stiffness. Around six weeks after injury, strengthening exercises begin, focusing on the muscles that stabilize the shoulder blade and the rotator cuff. Contact sports and heavy lifting are typically off-limits until 8 to 12 weeks after injury.
For higher-grade separations treated with a sling (typically worn for about 4 to 6 weeks), supervised physical therapy follows the same general pattern: restore motion first, then build strength. The overall timeline stretches longer, and returning to full activity without restriction may take three months or more.
Surgical recovery adds time on the front end, since the repaired ligaments need to be protected while they heal. Post-surgical patients can generally expect several months of structured rehab before returning to demanding physical activity.
The Bump May Stay
One thing that surprises many people: even after a full recovery, the bump on top of the shoulder often remains permanently, particularly with Type II and III injuries. The collarbone may sit slightly higher than it did before. This is usually cosmetic and doesn’t affect function once the surrounding muscles have been strengthened. Most people regain full range of motion and can return to their previous level of activity, though the timeline depends heavily on the grade of injury and how consistently they follow through with rehab.