Shoulder fractures most often involve the clavicle (collarbone), proximal humerus (top of the upper arm bone), or the scapula (shoulder blade). Shoulder dislocations can involve any of the three different joints that make up the shoulder.| orthoinfo.aaos.org
In a shoulder dislocation, the head of the upper arm bone (humerus) may come either partially or completely out of the socket. To treat a dislocation, your doctor will place the ball of your upper arm bone back into the shoulder socket, a procedure called a "reduction."| orthoinfo.aaos.org