What is a shoulder dislocation?
Very simply, a shoulder dislocation involves the upper arm bone popping out of the socket, which is part of the shoulder blade. Although dislocations are possible in virtually any joint in the body, the shoulder is most commonly affected as it is also the most mobile joint. There are three main ways a shoulder can be dislocated: anteriorly (forwards), posteriorly (backwards), and inferiorly (downwards).
In an anterior dislocation, the upper arm bone pops out in the forwards direction relative to the shoulder socket. This is the most common way shoulders are dislocated and account for up to 95% of all shoulder dislocations! Anterior dislocations are usually caused by a fall on an outstretched arm, or a direct blow to the shoulder. Following an anterior dislocation, the arm is usually held slightly away and rotated from the body.
Posterior dislocations involve a backwards displacement of the upper arm bone relative to the shoulder socket. Compared to anterior dislocations, these are much less common and usually happen as a result of extreme contractions of the muscles on the back of the shoulder blade (e.g., during a seizure or as a result of being electrocuted). In contrast to an anterior dislocation, the arm is usually held tightly against the body and rotated inwards.
Downwards dislocations are a rare type of dislocation and account for less than 1% of all shoulder dislocations. When the shoulder is inferiorly dislocated, the arm actually appears to be permanently held upwards or behind the head due to the way the upper arm bone is displaced. This can be caused by sudden forceful movement of the arm sideways and upwards (hyperabduction).
What should I do with a dislocated shoulder?
In the event of any shoulder dislocation, prompt medical treatment should be sought as there are many important structures in and around the shoulder that can be damaged due to the trauma (e.g., nerves, blood vessels). In between, the shoulder should be kept in its current position by using a sling or splint. In some cases, particularly with an anterior dislocation, the shoulder may spontaneously reduce or relocate itself. However, it is still recommended to seek medical treatment to ensure the integrity of other structures around the shoulder. Commonly, people with shoulder dislocations are advised to have an x-ray or MRI to visualize the condition of soft tissue and bony structures.
Depending on the extent of the injury, non-operative or surgical management may be undertaken. Non-operative management is recommended if the extent of the injury is minor, there is no compromise of nerves or blood vessels, and there is minor or no associated injury to the soft tissue or bony structures of the socket or upper arm bone. Non-operative management typically involves restricting movement for a short period of time and progressive shoulder strengthening and stabilization exercises to ensure adequate control of the shoulder joint during desired activities.