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:
- Subluxation—The humeral head moves part way out of the shoulder socket.
- Dislocation—The humeral head moves completely out of the socket.
- Anterior—The humeral head moves toward the front.
- Posterior—The humeral head moves toward the back.
Copyright © Nucleus Medical Media, Inc.
Last reviewedAugust 2014by John C. Keel, MD; Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.