Upper body skeleton. Computer artwork of a glass- effect human male body showing the skeletal structure of the head and torso. Inside the head is the skull (top), comprising the cranium or braincase, facial and jaw bones. The backbone or spinal column runs down the back of the body from the base of the skull to the pelvic bones (bottom). The ribcage (centre) is formed of twelve pairs of curved ribs that attach to the spinal column. The ribcage protects the organs of the thoracic cavity. The ribs attach at the front of the body to the sternum or breastbone (centre). At the top of the sternum are the collar bones, also known as clavicles (left & right, upper centre).