<Tr> <Th> FMA </Th> <Td> 13321 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terms of bone (edit on Wikidata) </Td> </Tr> <P> The clavicle or collarbone is a long bone that serves as a strut between the shoulder blade and the sternum or breastbone . There are two clavicles, one on the left and one on the right . 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 is a palpable bone and in people who have less fat in this region, the location of the bone is clearly visible, as it creates a bulge in the skin . It receives its name from the 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 fractured bone . It can easily be fractured due to impacts to the shoulder from the force of falling on outstretched arms or by a direct hit . </P> <P> The collarbone is a large doubly curved long bone that connects the arm to the trunk of the body . Located directly above the first rib it acts as a strut to keep the scapula in place so that the arm can hang freely . Medially, it articulates with the manubrium of the sternum (breastbone) at the sternoclavicular joint . At its lateral end it articulates with the acromion, a process of the scapula (shoulder blade) at the acromioclavicular joint . It has a rounded medial end and a flattened lateral end . </P>

How many collar bones in the human body