The classic sign is sharp pain on the very top of the shoulder, at a spot you can cover with one fingertip, that started when you landed on the point of your shoulder. Reaching across your chest makes it worse. So does lying on that side. Some people also see a bump where the collarbone ends.
Most of these injuries heal without surgery, including many with a visible bump. The job in the first few days is to rule out the things that look similar and are more serious, mainly a broken collarbone or a dislocated shoulder. This guide walks through AC joint injury symptoms as you actually notice them, what the grades mean, and which findings should send you for an X-ray or to the emergency department before anyone starts rehab.
Before the symptoms make sense, it helps to know which joint is actually hurt. It isn’t the one most people picture.
What the AC joint is, and what an injury to it is not
The acromioclavicular joint is the small joint on top of your shoulder where the outer end of the collarbone meets the acromion, the bony shelf of the shoulder blade. Two sets of ligaments hold it together: the AC ligaments around the joint itself, and the stronger coracoclavicular (CC) ligaments a little further in, which anchor the underside of the collarbone to the shoulder blade.
A “separated shoulder” is an injury to this joint. The usual cause is a fall straight onto the point of the shoulder, which strains or tears those ligaments. If the CC ligaments tear too, the shoulder blade drops under the weight of the arm and the end of the collarbone stands out as a bump [+].
It is easy to confuse with three other injuries:
- A dislocated shoulder: That is the ball-and-socket joint lower down, a different injury with a different plan.
- A broken collarbone: Same kind of fall, similar pain, and it can sit right next to the AC joint.
- A rotator cuff tear: More likely after 40, and the pain tends to sit on the outer arm rather than on top.
If you have shoulder pain physiotherapy questions that go beyond a fall, such as a slow-building ache or stiffness, that page covers the wider picture.
That anatomy is also why the pain is so easy to point to.
Why the pain behaves the way it does
The joint is small and sits right under the skin, so the pain is precise. People point to it rather than waving a hand over the whole shoulder. Anything that squeezes the two bone ends together loads the injured ligaments: reaching across your body, lying on that side, pushing up from a chair, a bench press.
They’re common. One clinical review puts them at more than 40% of all shoulder injuries, often from sport, falls or car crashes [+]. In the GTA the stories repeat every season: a hockey check into the boards, a cyclist going over the bars, a slip on January ice, a snowboarder catching an edge.
Most guides list symptoms by grade, as though the grade tells you how much it will hurt. It doesn’t. In a study of 77 people with acute AC injuries, the severity grade on X-ray showed no meaningful link with pain, strength, range of movement or shoulder function scores [+]. A mild sprain can hurt more in week one than a full separation. So read the next section as a way to describe what you’ve got, not to self-grade it.
AC joint injury symptoms, sorted by what you notice
Pain
- A sharp, pinpoint spot on top of the shoulder, right where the collarbone ends
- Worse reaching across your chest, reaching behind you, or lifting above shoulder height
- Worse lying on that side, which is why the first few nights are usually the hardest
- An ache that can spread into the neck or the top of the shoulder blade
What you can see
- Swelling on top of the shoulder within hours
- Bruising, sometimes appearing a day or two later and tracking down the arm
- A step or bump where the collarbone ends. It is more visible standing, with the arm hanging, than lying down
Movement and strength
- You can usually still lift the arm, it just hurts
- Weakness pushing or pressing, like opening a heavy door
- Holding the arm against your body for comfort, and avoiding overhead reaching
Sensations
- A pop felt at the moment of the fall
- Clicking or grinding at the joint in the weeks afterwards, most noticeable with pressing movements
Later on
- Pain that returns weeks later with push-ups, dips or bench press, even though daily life feels fine
- A bump that doesn’t go away. On its own this is often cosmetic rather than a problem
How the grades usually line up
Clinicians use the six-type Rockwood scale, which is why you’ll see “three grades” on some sites and “six types” on others. Types I to III describe increasing ligament damage and upward displacement of the collarbone. Types IV to VI describe the collarbone moving backward, sharply upward, or down under the shoulder blade structures. Those three are rare, and they come from high-energy trauma. Broadly:
- Type I: tender and sore, no bump, X-ray looks normal
- Type II: more pain and swelling, a slight step at the joint
- Type III: an obvious bump, both ligament groups torn
- Types IV to VI: severe injuries, usually with a very visible deformity. These are surgical conversations
Only an examination, and in many cases an X-ray, sets the type.
Categories tell you what you might have. What most people need to know after a fall is how fast to act.
How urgent is it? What to do and when
| What you notice | What to do |
|---|---|
| Arm hanging uselessly, the shoulder looks squared off or wrong, or you cannot move it at all | Go to the emergency department now |
| Numbness, pins and needles, or a cold or pale hand after the fall | Go to the emergency department now |
| Shortness of breath or chest pain after a high-speed crash or heavy impact | Go to the emergency department now |
| A bone end pressing against or tenting the skin, or a lump at the back of the shoulder rather than on top | Go to the emergency department now |
| A child or teenager with any of the symptoms above after a fall | Get it X-rayed the same day, through urgent care or the emergency department |
| An obvious bump on top, tenderness along the collarbone itself, or significant pain after a fall | Get an X-ray within a day or two, then physiotherapy |
| Pinpoint pain on top, no deformity, you can lift the arm | See a physiotherapist within a few days. An X-ray can be arranged if the exam points that way |
| Aching on top of the shoulder with pressing or lifting, no fall | Book an assessment. This may be AC joint wear rather than an injury |
Children and teenagers are on that list for a specific reason. Until the mid-twenties, the end of the collarbone is still growing, so a fall that would separate an adult’s AC joint often fractures through the growth plate instead. On X-ray it can look like a separation, and it sometimes needs different treatment [+].
In Ontario you can book a physiotherapist directly, but an X-ray needs a requisition from a physician or nurse practitioner. If you are in the “X-ray first” rows, walk-in clinics and urgent care centres can usually arrange that faster than waiting for a family doctor appointment.
The rows in that table exist because several injuries share the same fall and the same pain. Here is how they differ.
AC joint injury or something else?
- Broken collarbone. The tenderness runs along the bone itself rather than sitting at its tip, and there may be a bump partway along the collarbone. Moving the arm hurts in almost every direction. This one needs an X-ray.
- Dislocated shoulder. The shoulder loses its rounded outline and looks flat or squared off. The arm is usually held slightly away from the body, and almost any movement is refused. This is an emergency.
- Rotator cuff tear. Pain sits on the outer upper arm. Lifting the arm out to the side is weak, sometimes impossible, while the top of the shoulder isn’t especially tender to press. More common after 40 and after a fall onto an outstretched arm.
- Neck referral. Pain runs past the elbow, often with tingling, and turning your head changes it. Pressing on the AC joint doesn’t reproduce it.
- AC joint arthritis. Same spot, but no injury, and it builds slowly. Common in people who have pressed heavy weights for years.
Sorting between these is most of what the first appointment is for.
What happens at a physiotherapy assessment
A physiotherapy assessment for shoulder injuries starts with the story of the fall, because the direction and force of the impact already narrow things down. After that, most of the information comes from the exam.
We look at both shoulders side by side with your arms hanging, since a step at the joint is easiest to judge that way. We press along the collarbone and over the joint, which usually separates a fracture from an AC injury. Then comes the cross-body test: bringing your arm across your chest to see whether it reproduces the pain. We check how far you can lift and rotate the arm and how strong the rotator cuff is, and we screen the neck and the nerves to the arm.
If anything suggests a fracture, a high-grade separation, or a teenager’s growth-plate injury, you leave with a note for your doctor explaining why an X-ray is needed, rather than a rehab plan. If it looks like a Type I or II injury, you leave with a plan and a date to re-check.
Most people want to know what they can safely do before that appointment. The answer is narrower than you might think.
What you can do yourself in the first few days
This applies only if none of the emergency signs in the table are present. It keeps you comfortable. It doesn’t treat the injury, and it isn’t a replacement for being examined.
- Sling, briefly, if at all. A sling for comfort for the first few days is reasonable. Wearing one for weeks without being told to lets the shoulder stiffen.
- Keep the rest of the arm moving. Open and close your hand and bend and straighten your elbow and wrist, 10 times, several times a day.
- Ice for comfort. 10 to 15 minutes at a time over a thin towel, if it helps. It’s for pain relief, not healing.
- Sleep on your back or the other side, with a pillow supporting the injured arm.
- Skip the loading movements. No push-ups, bench press, dips, overhead pressing, or heavy bags on that shoulder until you’ve been assessed.
- Pain relief. If you want medication, ask a pharmacist which over-the-counter option suits you and your other medications.
Once a Type I or II injury is confirmed, rehab usually starts within the first week or two. Typical early work includes gentle movement below shoulder height and light isometric holds (for example, five 10-second holds, two or three times a day, kept to a mild pain level). It then progresses to shoulder blade control and strength. Your physiotherapist sets the dose, because it depends on your grade and what you need the shoulder to do.
The bump is what worries people most, usually because they assume it means an operation.
Does a bump mean you need surgery?
Usually not. Types I and II are managed without surgery. Type III is where opinion has been divided for decades, and the evidence has been drifting toward trying rehab first for most people.
Some of the strongest evidence came from Toronto. A Canadian multicentre trial run from St. Michael’s Hospital randomised 83 adults with complete separations (Types III to V) to surgical fixation or non-operative care. Surgery restored the joint’s position better, but it didn’t produce better outcomes than non-operative treatment [+].
The bump itself often stays. For most people it’s a cosmetic change, and AAOS notes that good, pain-free function often returns even when the bump is very large. Surgery still has a place: the rare high-grade types, some overhead athletes and manual workers, and people whose shoulder hasn’t improved after a properly run rehab programme. That decision belongs with an orthopaedic surgeon, and your physiotherapist can help you judge when a referral is worth it.
If you do end up having surgery, rehab afterwards follows the surgeon’s timeline, which is the territory of post-surgical rehabilitation.
What to do next
If you have any of the emergency signs, go to the emergency department. If there’s a bump or real doubt about a fracture, get an X-ray first. For everything else, book a shoulder assessment in the first week, keep the arm gently moving, and stop pressing and pushing movements until you have a plan. A Type I sprain is often back to normal within a few weeks. Higher grades take longer, and the timeline should come from your assessment rather than from a chart online.
Before you go
This article is general information, not a diagnosis. A sprained AC joint, a cracked collarbone and a teenager’s growth-plate injury can read almost the same on a page and look quite different under a clinician’s hands. Getting it examined early is how you avoid weeks of rehab on the wrong problem. If any of the emergency signs above apply, go to the emergency department first. Otherwise, book physiotherapy in Richmond Hill or physiotherapy in North York for a proper shoulder assessment.
Frequently asked questions
How do I know if I’ve separated my shoulder or just bruised it?
A bruise is tender over a broad area and doesn’t really change with cross-body reaching. An AC injury hurts at a pinpoint spot on top and flares when you bring the arm across your chest. A visible step at the joint points to a separation. An exam settles it.
Can I still move my arm with an AC joint injury?
Usually, yes. Most people can lift the arm, just painfully. Being unable to move it at all, or the shoulder looking flat or squared off, suggests a dislocation or fracture and needs the emergency department.
Will the bump go away?
With Type I there’s no bump to begin with. With Type II and III injuries it often stays, whether or not you have rehab. It rarely affects how well the shoulder works in the long run.
How long do AC joint injury symptoms last?
With a mild sprain, AC joint injury symptoms often settle over one to three weeks. More significant injuries usually take six weeks or longer before pressing and overhead work feel normal. Pain with heavy pressing can linger past that.
Do I need an X-ray?
Not always. You do if there is a visible bump, tenderness along the collarbone, a high-energy injury, or if the injured person is a child or teenager. In Ontario a physician or nurse practitioner orders it, and your physiotherapist can tell you whether it’s needed.
Should I keep going to the gym?
Lower body and cardio, generally yes. Pressing, push-ups, dips and heavy pulling should wait until you’ve been assessed and have a return plan, because they load exactly the ligaments that are healing.