Common Conditions
Shoulder Dislocation
Symptoms, Common Causes and Treatments
What Is a Shoulder Dislocation?
The shoulder is the most mobile joint in the body — and that mobility comes at the cost of stability. A dislocation (in Cantonese, commonly called 甩骹 occurs when the ball of the humerus is displaced from the glenoid socket. This can happen partially (subluxation) or completely (full dislocation).
There are three main types:
- Anterior dislocation (≈95% of cases) — the humeral head shifts forward, usually from a fall on an outstretched arm or a blow while the arm is raised and rotated outward (common in basketball, rugby, and rock climbing).
- Posterior dislocation — less common, often linked to seizures, electric shock, or a direct blow to the front of the shoulder.
- Inferior dislocation — rare, where the arm is forced straight downward.
Common Causes
- Falling onto an outstretched hand
- Direct contact sports (rugby, basketball, martial arts)
- Sudden forceful rotation of the arm
- Repetitive overhead movement in swimmers, climbers, and volleyball players
- Pre-existing joint hypermobility or a previous dislocation (the single biggest risk factor for recurrence)
Symptoms
- Visibly deformed or “out of place” shoulder
- Severe pain and inability to move the arm
- Swelling and bruising around the joint
- A sensation of the shoulder being loose, unstable, or “slipping”
- Numbness or tingling down the arm (may indicate nerve involvement — seek urgent care)
*Seek immediate medical attention at a hospital or emergency department if you suspect a dislocation — the joint must be professionally relocated (“reduced”) by trained medical staff. Do not attempt to force it back into place yourself.
