Overview

A dislocated shoulder is an injury in which your upper arm bone pops out of the cup-shaped socket that's part of your shoulder blade. The shoulder is the body's most mobile joint, which makes it susceptible to dislocation.

If you suspect a dislocated shoulder, seek prompt medical attention. Most people regain full shoulder function within a few weeks. However, once you've had a dislocated shoulder, your joint may become unstable and be prone to repeat dislocations.

Symptoms

Dislocated shoulder signs and symptoms may include:

  • A visibly deformed or out-of-place shoulder
  • Swelling or bruising
  • Intense pain
  • Inability to move the joint

Shoulder dislocation may also cause numbness, weakness or tingling near the injury, such as in your neck or down your arm. The muscles in your shoulder may spasm from the disruption, often increasing the intensity of your pain.

When to see a doctor

Get medical help right away for a shoulder that appears dislocated.

While you're waiting for medical attention:

  • Don't move the joint. Splint or sling the shoulder joint in its current position. Don't try to move the shoulder or force it back into place. This can damage the shoulder joint and its surrounding muscles, ligaments, nerves or blood vessels.
  • Ice the injured joint. Applying ice to your shoulder can help reduce pain and swelling by controlling internal bleeding and the buildup of fluids in and around your shoulder joint.

Causes

The shoulder joint is the most frequently dislocated joint of the body. Because it moves in several directions, your shoulder can dislocate forward, backward or downward, completely or partially, though most dislocations occur through the front of the shoulder. In addition, fibrous tissue that joins the bones of your shoulder can be stretched or torn, often complicating the dislocation.

It takes a strong force, such as a sudden blow to your shoulder, to pull the bones out of place. Extreme rotation of your shoulder joint can pop the ball of your upper arm bone out of your shoulder socket. Partial dislocation — in which your upper arm bone is partially in and partially out of your shoulder socket — also may occur.

A dislocated shoulder may be caused by:

  • Sports injuries. Shoulder dislocation is a common injury in contact sports, such as football and hockey, and in sports that may involve falls, such as downhill skiing, gymnastics and volleyball.
  • Trauma not related to sports. A hard blow to your shoulder during a motor vehicle accident is a common source of dislocation.
  • Falls. You may dislocate your shoulder during a fall, such as from a ladder or from tripping on a loose rug.

Risk factors

Males in their teens or 20s, a group that tends to be physically active, are at highest risk of shoulder dislocation.

Complications

Complications of a dislocated shoulder may include:

  • Tearing of the muscles, ligaments and tendons that reinforce your shoulder joint
  • Nerve or blood vessel damage in or around your shoulder joint
  • Shoulder instability, especially if you have a severe dislocation or repeated dislocations, which makes you more prone to re-injury.

If you stretch or tear ligaments or tendons in your shoulder or damage nerves or blood vessels around your shoulder joint, you may need surgery to repair these tissues.

Prevention

To help prevent a dislocated shoulder:

  • Take care to avoid falls
  • Wear protective gear when you play contact sports
  • Exercise regularly to maintain strength and flexibility in your joints and muscles

Once you've dislocated your shoulder joint, you may be more susceptible to future shoulder dislocations. To avoid a recurrence, follow the specific strength and stability exercises that you and your doctor have discussed for your injury.

Aug. 16, 2014
References
  1. Sherman SC, et al. Shoulder dislocation and reduction. http://www.uptodate.com/home. Accessed June 30, 2014.
  2. Dislocated shoulder. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=a00035. Accessed June 30, 2014.
  3. Questions and answers about shoulder problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Shoulder_Problems/default.asp. Accessed June 30, 2014.
  4. Traumatic shoulder dislocation. American Orthopaedic Society for Sports Medicine. http://www.sportsmed.org/Patient/Sports_Tips/AOSSM_Sports_Tips_Sheets/. Accessed June 30, 2014.
  5. Zacchilli MA, et al. Epidemiology of shoulder dislocations presenting to emergency departments in the United States. The Journal of Bone and Joint Surgery. 2010;92:542.