The shoulder is a highly mobile joint, allowing the arm to move in almost any direction. The joint is formed by the connection of the humerus (the upper arm bone) and the scapula (shoulder blade). The articular end of the humerus is rounded and fits into a shallowly concave surface of the scapula called the glenoid fossa, forming a flexible ball-and-socket joint. Helping to stabilize the joint are ligaments running from bone to bone, tendons that connect bone to muscle, and a ring of cartilage surrounding the glenoid.
The flexibility of the joint and the shallowness of the glenoid fossa means that the joint is fundamentally unstable and the humerus can quite easily be pushed out of place as a result of a trauma. The joint may be completely or partially dislocated, and the shoulder muscles, ligaments, and tendons stretched or torn. There may also be nerve or blood vessel damage.
A severe dislocation will increase the risk of repeated shoulder dislocations.
The shoulder is the most commonly dislocated joint in the body. Dislocations are usually caused by trauma, either falling onto the shoulder, or receiving a strong blow to the shoulder, often during contact sports or a vehicle accident. Attempting to break a fall by stretching out an arm can also result in dislocation, as can sharply twisting the arm.
Some sports carry a higher than usual risk of sustaining a dislocated shoulder. These include football, hockey, soccer, rugby, volleyball, rock climbing, and skiing.
The main symptoms are:
- Severe pain, felt in the shoulder and upper arm, made worse with movement
- A visible deformity in the front or back of the shoulder, depending on the dislocation
- Swelling or bruising, increasing with time
- Possible numbness or tingling in the neck or down the arm
- Muscle spasm, causing extreme pain and unwillingness to move the arm at all
While waiting for medical attention, immobilize the joint. Do not try to reposition it yourself as further damage might result. Ice can be applied to relieve swelling.
Your doctor will ask you questions relating to the circumstances of the injury, and any previous injuries to the shoulder that you might have suffered. A physical examination of the arm and shoulder will help your doctor determine whether there is a dislocation. X-rays may be taken if broken bones are suspected, and possibly an MRI (magnetic resonance image) scan if the soft tissues of the joint need to be viewed in greater detail.
Because a dislocated shoulder is extremely painful, and swelling will increase with time, it is important to reposition the joint as soon as possible. Your doctor will, if achievable, physically manipulate the arm back into the shoulder socket in a procedure known as a closed reduction. You will probably be given a muscle relaxant or sedative before this is done. Once your shoulder bones are back in position, the pain normally diminishes significantly. Another X-ray may be taken to confirm the reduction.
To help relieve pain and swelling, ice can be applied to the shoulder. The ice should be crushed in a bag, the bag wrapped in a towel, and placed on the shoulder for as long as is comfortable, several times a day.
Over-the-counter pain medication can be taken, such as NSAIDs (non-steroidal anti-inflammatory drugs). Examples of such drugs are Advil, Motrin and Aleve.
Your doctor will advise you as to whether you should wear a sling or shoulder immobilizer. If necessary, you will probably need to wear it for a period lasting from a few days to three weeks. You will also receive advice about rehabilitation of the shoulder. When you should start gentle stretching and strengthening exercises will depend on your particular injury. It is very important to follow medical advice, as trying to resume normal activity before the shoulder is completely healed could result in permanent damage to the joint.
Most dislocated shoulders are treated with conservative (non-surgical) methods such as those described above, but in some cases, surgery will be necessary. Such instances might include a situation where damage to blood vessels and nerves needs to be repaired, or repeated dislocations have loosened the tendons around the joint, so that they need to be surgically tightened.
Your health care provider or physical therapist will design an exercise program specifically for you, but, with medical approval, doing the following exercises will help you begin to rehabilitate your shoulder.
Isometric external rotation:
Stand in a doorway with the injured shoulder nearest the doorframe. Bend the elbow and press the back of the wrist against the doorframe. Hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Isometric internal rotation:
Standing just to the side of a doorway, bend the elbow of the injured arm and press the front of the wrist against the doorframe. Hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Hold a pillow between the chest and arms. Squeeze the pillow and hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Stand with your back to a wall so that your bent elbows just touch the wall. Press your elbows back against the wall and hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Standing with your arms straight by your sides. Keeping your elbows straight, lift your arms up as high as you can. Hold for 5 seconds. Repeat 10 times.
Stand with your arms straight by your sides. Keeping your elbow straight, move one arm backwards as far as it will go, without forcing. Hold for 5 seconds. Repeat 10 times. Repeat exercise with the other arm.
Standing with your arms at your sides, slowly lift the arms straight out and up. Hold for 5 seconds. Repeat 10 times.
Wear proper protective equipment if you play contact sports, and make sure that you exercise regularly to keep your joints and muscles strong and flexible.