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 partially 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. Inferior—The humeral head drops downward.Multidirectional—The humeral head moves toward difference places.
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Shoulder instability often results from injury.
Factors that may increase your chance of shoulder instability include: Trauma, such as a fall with an outstretched arm or a direct blow to the shoulder
Previous shoulder dislocationAthletic activity, especially: Baseball—pitchingFootball—tacklingTennisGymnasticsWeight-liftingAny collision or contact sportVolleyballSwimming, especially backstroke or butterfly
Congenital collagen disorders, such as:
Marfan syndrome—a connective tissue condition
Ehlers-Danlos syndrome—a condition marked by loose joints
Family members with shoulder instability
Symptoms may come on suddenly or develop over time. Shoulder instability may cause: Pain in the shoulder areaShoulder or arm weaknessShoulder may feel looseShoulder may slip out of placeNumb feeling down the arm
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.
Imaging tests evaluate your shoulder and surrounding structures. These may include: X-raysMRI scanCT scan
Arthroscopy is done with an instrument with a long tube and miniature camera on the end. Repairs or corrections can be made while the doctor evaluates the shoulder joint.
Therapy will depend on the extent of the injury, the cause, and other factors. Treatment may include: Rest—Avoid activities that produce pain or stress the joint.Ice—This helps to control pain and inflammation, especially after exercise.
Medication—Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin or ibuprofen, may be given to manage pain.
Rehabilitation—This can last several months and may include:
Physical therapy to strengthen the muscles that control the shoulder joint, particularly the internal rotators of the shoulderSpecific exercises for certain sports or job activitiesLearning how to modify activities to prevent reinjury
Surgery—Many different procedures may be used to correct shoulder instability. The goal is to fix the cause. An
or an open technique may be used. After surgery, the arm is kept from moving for 3 to 6 weeks, depending on the procedure.
Guidelines to help protect the shoulder from injury include: Doing regular exercises to strengthen the supporting musclesUsing proper athletic training methodsIncreasing the duration or intensity of your exercises graduallyModifying activities to prevent excessive external rotation and overhead motions of the shoulder
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Last reviewed September 2015 by Laura Lei-Rivera, DPT
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.
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