Shoulder dislocations are injuries where the humeral head (ball) of humerus (upper arm bone) is no longer articulating (in contact) with the glenoid (socket) of the shoulder joint. The most common dislocation is anterior (more than 90 percent), where the humeral head dislocates out in front and below the glenoid socket. Because the shoulder has more motion than any other large joint in the body, it is the most commonly dislocated large joint.
X-ray of anterior shoulder dislocation
There are many structures that work together to provide shoulder stability and include the bone of the humeral head and glenoid, the glenoid labrum (a thickening of soft-tissue surrounding the glenoid socket), the capsule and ligaments which connect the humerus to the glenoid, and the tendons of the rotator cuff muscles which surround the shoulder. Any or all of these anatomic structures may be damaged with a shoulder dislocation and may require repair.
Frequent Signs and Symptoms
- Apprehension, feeling like the shoulder is going to “pop out”
- Pain with moving the shoulder, especially when reaching overhead; pain with heavy lifting; pain with carrying objects with the arm at the side; pain that awakens you at night
- Loss of shoulder strength and function
- Tenderness and occasionally swelling
- Numbness or paralysis in the upper arm and deltoid muscle from pinching, stretching, or pressure on the blood vessels or nerves
- Feeling and sound of crepitation (“crackling”) when the injured area is touched or with shoulder motion
- Repeat dislocation