A dislocated collarbone typically shows up as a visible bump or protrusion near the shoulder or breastbone, depending on which end of the bone has shifted out of place. The collarbone connects to your body at two joints, one at each end, and the appearance of the injury differs based on which joint is involved and how far the bone has moved. In mild cases you might see little more than swelling, while severe dislocations create an obvious deformity that’s hard to miss.
Where the Collarbone Can Dislocate
Your collarbone acts like a strut connecting your shoulder blade to your breastbone. It has a joint at each end. The outer end meets your shoulder blade at the acromioclavicular (AC) joint, right on top of your shoulder. The inner end meets your breastbone at the sternoclavicular (SC) joint, just below the base of your neck. AC joint dislocations are far more common. When people talk about a “separated shoulder,” they’re usually describing an AC joint injury. SC joint dislocations are rarer but can look quite different.
What an AC Joint Dislocation Looks Like
The hallmark sign of an AC joint dislocation is a bump on the top of your shoulder where the outer end of the collarbone pushes upward. In mild injuries, this bump is subtle and you might only notice tenderness and minor swelling over the joint. In moderate injuries, the joint widens and the collarbone sits slightly higher than the shoulder blade, creating a small but visible step in the skin’s contour.
In severe cases, the collarbone rises dramatically. The bump becomes unmistakable, sometimes described as a “step-off” deformity because it looks like a stair step in the shoulder’s normally smooth profile. Bruising and swelling often surround the area, and the skin over the protruding bone may look stretched or tight. The affected shoulder tends to droop downward and forward compared to the uninjured side because the ligaments that normally hold the collarbone in place are completely torn.
One classic test involves pressing down gently on the raised end of the collarbone. If it springs back up when you release pressure, like pressing a piano key, that’s a strong indicator the joint is unstable. This deformity becomes more obvious when you’re standing or sitting upright, because the weight of your arm pulls the shoulder down while the collarbone stays elevated.
How Severity Changes the Appearance
Doctors grade AC joint injuries on a scale from Type I through Type VI, and the visual changes track closely with severity. Type I and II injuries look relatively normal from the outside. You’ll see swelling and maybe some bruising, but the collarbone hasn’t shifted enough to create an obvious bump. By Type III, the collarbone has displaced upward anywhere from 25% to 100% compared to the other side, producing a noticeable lump. Type V injuries are the most visually dramatic of the common types: the collarbone rises to two or three times its normal distance from the shoulder blade, creating a large, tented bump under the skin. Type IV injuries push the collarbone backward into the muscle behind the shoulder, which can be harder to see but creates a peculiar flattening of the normal shoulder contour. Type VI, which is extremely rare, sends the collarbone downward beneath the shoulder blade, reversing the usual deformity.
What an SC Joint Dislocation Looks Like
When the inner end of the collarbone dislocates near the breastbone, the appearance depends on which direction the bone moves. In an anterior dislocation (the more common type), you’ll see a painful, hard lump just to one side of the notch at the top of your breastbone. It’s usually tender to touch and sits right beneath the skin, making it easy to spot when comparing both sides of the chest.
Posterior dislocations push the collarbone backward, behind the breastbone. These are harder to see. Instead of a visible bump, you might notice a subtle depression or hollowing where the inner end of the collarbone should be, along with some bruising below the area. Posterior dislocations are more concerning because the collarbone can press against structures behind the breastbone, including the windpipe and major blood vessels.
How It Differs From a Broken Collarbone
A dislocated collarbone and a fractured one can look similar at first glance, and telling them apart without an X-ray can be difficult. Both cause swelling, bruising, and visible deformity. But there are some visual differences worth knowing.
A fracture, especially a displaced break in the middle of the collarbone, tends to create an angular, tent-like deformity partway along the bone’s length. The broken ends shift in opposite directions: the outer piece drops downward with the weight of the arm while a neck muscle pulls the inner piece upward. This produces a sharp, pointed bump in the middle third of the collarbone rather than at either end. If you run your finger along the bone, you may feel a gap or an abnormal angle at the fracture site.
A dislocation, by contrast, creates its bump specifically at one of the two joints, either right on top of the shoulder or beside the breastbone. The bone itself remains intact, so you won’t feel a break along its length. That said, fractures near the inner end of the collarbone can look nearly identical to an SC joint dislocation on visual inspection alone, which is one reason imaging is important for an accurate diagnosis.
Swelling, Bruising, and Color Changes
In the first few hours after injury, the area around the dislocated joint swells noticeably. Bruising typically develops within a day or two and appears red or purplish at first. On darker skin tones, bruising may look deep purple, dark brown, or black. As healing progresses over the following one to two weeks, bruises gradually shift to lighter shades of brown, green, or yellow before fading completely. The swelling usually peaks in the first 48 to 72 hours and then slowly subsides.
Keep in mind that the bony bump itself may not go away even after pain and swelling resolve. In moderate to severe AC joint dislocations treated without surgery, a cosmetic bump on the shoulder often remains permanently. It’s painless for most people but can be a lasting visible reminder of the injury.
When the Appearance Signals Something Serious
Most collarbone dislocations are painful but manageable. A few visual signs, however, suggest you need urgent medical attention. If the skin over the protruding bone looks white or blanched, that means the bone is pressing hard enough against the skin to cut off blood flow. This “skin tenting” can eventually cause the skin to break down, turning a closed injury into an open one. Case reports have documented initially closed injuries converting to open fractures when the overlying tissue lost its blood supply and died.
Significant asymmetry at the base of the neck, where one side looks hollowed out compared to the other, may point to a posterior SC joint dislocation. If this is accompanied by difficulty swallowing, voice changes, or shortness of breath, the displaced bone may be compressing vital structures and needs immediate evaluation.
What Happens After Diagnosis
Mild to moderate AC joint dislocations (Types I and II) are almost always treated with rest, ice, a sling, and gradual rehabilitation. The bump may stay but function typically returns fully. Type III injuries fall in a gray area where treatment depends on your activity level, symptoms, and preferences. Severe injuries (Type V and above) generally require surgery to reposition and stabilize the collarbone.
Conservative treatment can occasionally leave a larger cosmetic deformity than expected, along with persistent pain or shoulder instability in some patients. For people whose work or sport demands full overhead strength, this factors into the decision about whether surgery is worthwhile. For most everyday activities, the visible bump from a moderate dislocation doesn’t affect function once the ligaments have healed and the surrounding muscles have been rehabilitated.