Shoulder instability occurs when the upper-end of the arm bone, known as the humerus, slides partially or completely out of the shoulder socket.
The disorder is classified by how much the humerus moves and the direction of the movement:
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Factors that increase the risk of shoulder instability include:
Symptoms may come on suddenly or develop over time. Symptoms may include:
You will be asked about your symptoms and medical history. A physical exam will be done. Special attention will be given to your shoulders. Your doctor will determine your range of motion and try to move the humeral head within the socket.
Your shoulder may need to be viewed. This can be done with:
Therapy will depend on the extent of the injury, the cause, and other factors. Treatment may include:
Guidelines to help protect the shoulder from injury include:
American Academy of Family Physicians
American Academy of Orthopaedic Surgeons
Canadian Orthopaedic Association
Canadian Orthopaedic Foundation
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Last reviewed November 2013 by John C. Keel, MD; Michael Woods, MD
Last Updated: 11/21/2013