The shoulder is the most mobile joint in the human body.

Because of its wide range of movement, it is suspectible to dislocation.

A dislocation occurs when the ball of your humerus (upper bone arm) – called your humeral head, pops out of its socket – called the glenoid.

The glenoid is actually part of your shoulder blade (scapula). It forms a shallow cup or socket, which the ball of your humerus sits in.
50% of all joint dislocations involve the shoulder, particularly in young people.

Every year, 12 out of 100,000 people sustain a shoulder dislocation for the first time.

95% of shoulder dislocations occur anteriorly – the ball pops out the front.

More rarely, the shoulder can pop out the back.

Dislocations of the shoulder can occur due to an injury or trauma, such as falling heavily onto the arm or shoulder, or can occur without a traumatic injury.

Further Reading and References