Broken upper arm bone. Coloured X-ray of the left shoulder of a patient, showing a fracture (upper right) of the upper arm bone (humerus). The neck of the humerus has fractured, separating its head (upper right) from its shaft (lower right). This type of injury would require the bone to be pinned in place to heal. The humeral head articulates with the scapula (shoulder blade, upper left) forming the ball-and-socket shoulder joint (upper centre). Above the scapula, lies the clavicle (collar bone) that articulates with the scapula. The ribs of the chest are at left.