The main shoulder joint is a ball and socket arrangement with the ball held into the socket with ligaments and the muscles. The socket in the shoulder blade is small compared to the ball at the top of the arm bone. Much of the ball is not actually in the socket at all. This gives us great movement ranges in our arms which can move a long way in almost any direction. However, it does mean that sometimes the ball can slip out of the socket. This is a shoulder dislocation.

The ball is at the head of the humerus. The socket is called the glenoid and is extended by soft cartilage known as the labrum. By far the most dislocations occur when the head of the humerus is pushed out of the front of the glenoid. This often damages the labrum on the way.

This usually occurs when the arm is out and turned with the palm to the front. Force applied then pushes the joint further than it is used to and the ligaments will not be able to do their job. A common scenario is where a person puts their arm out to break a fall. In women, the most common age to suffer this injury is in the 60s and is caused by just this type of fall.

The most common age for men to dislocate their shoulders is in their 20s. Here, the extra pressure on the joint usually comes during contact sport. The additional force applied is usually from another player rather than just the weight of the patient themselves. Young men suffering this injury are statistically at a much greater risk of repeating it later in life.

This is a traumatic injury in anyone and patients need expert and preferably immediate medical assistance from an Orthopedic surgeon.