AC joint sprain (shoulder separation)

What it is

The collarbone meets the shoulder blade at a small joint on the top of the shoulder, the acromioclavicular or AC joint, held together by a capsule and two sets of ligaments. A sprain stretches or tears those ligaments. Mild ones are painful but the joint stays lined up. More severe ones let the collarbone ride up, which is the visible bump people call a separated shoulder. This is a different injury from a dislocated shoulder, which is the ball leaving the socket.

How volleyball causes it

Almost always a direct landing on the point of the shoulder. Indoors that is a dive where the shoulder hits the floor before the chest, a collision with a teammate chasing the same ball in the seam, or an awkward landing off a block under the net. Sand is kinder, but beach players still get it by committing to a full extension dig and driving the shoulder into the sand at a bad angle. There is also a slower version in players who press a lot, where the joint surfaces themselves get irritated by repeated compression at the top of the block and in the weight room.

BlockingDefensePassingAttacking

What it feels like

• Pain you can cover with one fingertip, right on top of the shoulder where the collarbone ends
• A step or bump on the top of the shoulder compared with the other side
• Reaching across your body towards the opposite shoulder hurts sharply
• Pain lying on that side, and pain at the top of the block press or at overhead contact
• It hurts when someone presses directly on the joint and not when they press anywhere else
• Bruising and swelling over the top of the shoulder in the first few days

Stop and get it seen if

• An obvious deformity with the collarbone tenting or threatening the skin, or an arm that hangs and cannot be lifted. That is a high grade separation or a fracture.
• Numbness, pins and needles, coldness, or a weak pulse in the arm, which means nerves or blood vessels may be involved.
• Point tenderness along the shaft of the collarbone or in the neck rather than on the joint itself, which suggests a broken bone.
• Broken skin over the joint, or fever and spreading redness in the days afterwards.
• Chest pain or difficulty breathing after the same fall, which needs assessment for a rib or lung injury.

What recovery usually looks like

Stages, not a schedule. Everyone moves through these at their own pace, and the ranges are wide because real recoveries are.

1. 1. Acute settling

   3 days to 3 weeks depending on how severe the sprain is

   Protect the joint and control swelling while the ligaments start healing, keeping the elbow, wrist and the rest of the body training

   • Resting pain fading
   • The arm can be raised in front of you without severe pain
   • Swelling and bruising settling
   • Sleeping is comfortable on the back or the other side

2. 2. Range and strength

   2 to 8 weeks

   Get the arm overhead again and rebuild the blade and cuff muscles that pain shut down

   • Full overhead reach without a catch of pain
   • Cross body reach comfortable
   • Pressing and pulling loaded without pain at the joint
   • Any residual bump is stable and no longer sore to touch

3. 3. Back to contact and overhead

   2 to 10 weeks, and considerably longer for high grade injuries

Ready to play again when

• Full overhead range and full cross body reach without pain
• Pain free pressing and blocking at the top of the reach
• Willing and able to land on that shoulder in a controlled dive
• Pressing and pulling strength matched side to side
• Any remaining bump is painless and stable, which is common and does not by itself mean you are not ready

Keeping it from coming back

This is ordinary training, so unlike the rest of this page it does tell you what to do.

• Drill diving and the shoulder roll properly, starting on mats. Most AC injuries are a landing skill problem, and landing chest first with the arms extended keeps the point of the shoulder off the floor.
• Build the upper back and blade with rows, face pulls and prone Y raises so the shoulder is not sitting forward and exposed when you land.
• Call the ball loudly. Teammate collisions in the seam account for a real share of these.
• Balance heavy horizontal pressing with pulling, and change grip width or bar path if the top of the shoulder aches after benching, since repeated compression irritates this joint over time.
• Land block jumps under your own body with control rather than drifting into the net or into a teammate.