The shoulder is the most commonly dislocated joint. This is probably because the shoulder is also the most mobile joint in the human body and to achieve this its socket is almost flat and the joint relies on soft tissues such as ligaments and muscles to maintain stability. There are 3 general types/causes of shoulder dislocation: traumatic (most common), atraumatic due to hyperlaxity, and muscle patterning (rare). Some patients may have subtle elements of more than one of these types/causes. Shoulder dislocations due to trauma and injury are most common and of these anterior shoulder dislocation is the most common (90%). Posterior dislocation is a rare form of traumatic dislocation often caused by seizure or electrocution.
In this video we discuss the causes and management of traumatic shoulder dislocations: