Your shoulders are your body's most mobile joints. But the ability to move in many directions can leave your shoulders prone to injury.
The top of your shoulder blade (acromion) meets the end of your collarbone (clavicle) at the acromioclavicular (AC) joint. A stretch or tear of the ligaments of this joint — often due to a fall directly on the shoulder — is known as a separated shoulder. By contrast, a dislocated shoulder is a more extensive injury in which the upper arm bone (humerus) pops out of its cup-shaped socket.
If you suspect a dislocated shoulder, seek prompt medical attention. Most people regain full shoulder function within a few weeks after experiencing a dislocated shoulder. However, once you've had a dislocated shoulder your joint may become unstable and be prone to repeat dislocations.
The shoulder joint is the most frequently dislocated joint of the body. Because it can move in many directions, your shoulder can dislocate forward, backward or downward, completely or partially. In addition, fibrous tissue that joins the bones of your shoulder (ligaments) can be stretched or torn, often complicating the dislocation.
When your shoulder dislocates, a strong force, such as a sudden blow to your shoulder, pulls the bones in your shoulder out of place (dislocation). Extreme rotation of your shoulder joint, such as during a throwing movement, can pop the ball of your upper arm bone (humerus) out of your shoulder socket (glenoid), which is part of your shoulder blade (scapula). Partial dislocation (subluxation) — 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 :
Risk Factor :
- 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.
Dislocated shoulders are most common in people between the ages of 18 and 25 because these people tend to have a high level of physical activity. Older adults also are more susceptible to shoulder dislocation because their joints and surrounding ligaments are weaker. In addition, older people tend to fall more frequently, which can increase their risk of a dislocated shoulder.
When to seek medical advice :
It can be difficult to tell a broken bone from a dislocated bone. If you or your child appears to have a dislocated shoulder, get medical help right away.
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.
A dislocated shoulder joint may be :
- Visibly deformed or out of place
- Swollen or discolored (bruised)
- Intensely painful
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.
Besides physically examining your shoulder, your doctor may order the following tests :
- X-ray. An X-ray of your shoulder joint will show the dislocation and may reveal broken bones or other damage to your shoulder joint.
- MRI. Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to create cross-sectional images to help your doctor assess damage to the soft tissue structures around your shoulder joint.
- Arthrogram. Contrast fluid may be injected into your shoulder to highlight certain structures of your shoulder joint during an X-ray. If your shoulder has been dislocated severely or repeatedly, the contrast fluid may leak into an area of your shoulder joint where it normally shouldn't, indicating a tear or abnormal opening or blockage, such as those caused by ligament or nerve damage.
- Electromyography (EMG). An EMG is a procedure that measures the electrical discharges produced in your muscles. An instrument records the electrical activity in your muscle at rest and as you contract the muscle. Analyzing the electrical signals may help your doctor evaluate nerve damage caused by severe or repeated shoulder dislocation.
Sometimes a dislocated shoulder can cause the muscles, ligaments or tendons that reinforce your shoulder joint to tear. Occasionally a dislocation can lead to nerve or blood vessel damage in or around your shoulder joint. If dislocated severely or repeatedly, your shoulder may be more susceptible to reinjury (shoulder instability). If ligaments or tendons in your shoulder have been stretched or torn, or if nerves or blood vessels surrounding your shoulder joint have been damaged, you may need surgery to repair these tissues.
Treatment for a dislocated shoulder involves putting your shoulder bones back into place. Your doctor may try some gentle maneuvers to help your shoulder bones back into their proper positions — a process called closed reduction. Depending on the amount of pain and swelling, you may need a muscle relaxant or sedative or, rarely, a general anesthetic before manipulation of your shoulder bones.
When your shoulder bones are back in place, any severe pain should improve almost immediately. However, your doctor may immobilize your shoulder with a special splint or sling for several weeks. How long you wear the splint or sling depends on the nature of your shoulder dislocation. Your doctor may also prescribe a pain reliever or a muscle relaxant to keep you comfortable while your shoulder heals.
Regaining your strength
After your shoulder splint or sling is removed, you'll begin a gradual rehabilitation program designed to restore range of motion and strength to your shoulder joint. Avoid strenuous activity involving your injured shoulder until you've regained full movement and normal strength and stability in your shoulder.
If you've experienced a fairly simple shoulder dislocation without major nerve or tissue damage, your shoulder joint likely will return to a near-normal or fully normal condition. But trying to resume activity too soon after shoulder dislocation may cause you to injure your shoulder joint or to dislocate it again.
If your doctor can't move your dislocated shoulder bones back into position by closed reduction, surgical manipulation (open reduction) may be necessary. You may need surgery if you have a weak shoulder joint or ligaments and tend to have recurring shoulder dislocations (shoulder instability). In rare cases, you may need surgery if your nerves or blood vessels are damaged due to the dislocation.
To help prevent a dislocated shoulder :
- Take precautions 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.