Separated shoulder injuries often occur when falling on the shoulder, collision with another player or while being tackled. During the fall the shoulder will hit the ground and the shoulder blade will be pushed down. The clavicle (collar bone) can only partially follow this movement and there will be a great deal of strain on the ligaments causing them to rupture or dislocate.The acromioclavicular joint injuries are most commonly divided into three groups:

• Type I –  In a type I is a partial injury to the joint capsule. Paired whit an incomplete tear of the acromioclavicular ligaments and joint capsule.
• Type II – A type II injury is a moderate injury. A partial tear of the ligament coracoclavicular (ligament between coracoideus and clavicle) with a rupture of the capsule and the acromioclavicular ligament. Often described as a subluxation.
• Type III – A type III injury is a severe injury. Complete rupture of the acromioclavicular ligament but also the coracoclavicular ligament. This can lead to displacement of the clavicle and are therefore very unstable.