Collarbone

Clavicle (collarbone)
Collarbone (shown in red)
Human collarbone
Details
Identifiers
Latin	Clavicula
MeSH	A02.835.232.087.227
TA	A02.4.02.001
FMA	13321
Anatomical terms of bone []

In human anatomy, 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 broken 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.

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.

From the roughly pyramidal sternal end, each collarbone curves laterally and anteriorly for roughly half its length. It then forms an even large posterior curve to articulate with the acromion of the scapula. The flat acromial end of the collarbone is broader than the sternal end. The acromial end has a rough inferior surface that bears a ridge, the trapezoid line, and a slight rounded projection, the conoid tubercle (above the coracoid process). These surface features are attachment sites for muscles and ligaments of the shoulder.