Clavicle

The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavicle is the only long bone in the body that lies horizontally. Together with the shoulder blade, it makes up the shoulder girdle. It receives its name from Latin clavicula 'little key' because the bone rotates along its axis like a key when the shoulder is abducted. The clavicle is the most commonly broken bone. It can easily be fractured by impacts to the shoulder

subclavian groove

oblique line for trapezoid lig