In human anatomy, the<unk>  or collar bone is classified as a long bone that makes up part of the shoulder girdle (pectoral girdle). It receives its name from the Latin<unk> icula ("little key") because the bone rotates along its axis like a key when the shoulder is abducted. (This movement is palpable with the opposite hand).  In some people, particularly females who may have less fat in this region, the location of the bone is clearly visible as it creates a bulge in the skin.
The<unk>  is a doubly-curved long bone (the only horizontal long bone in the human body) that connects the arm (upper limb) to the body (trunk), located directly above the first rib.  Medially, it articulates with the manubrium of the sternum (breast-bone) at the sternoclavicular joint.  At its lateral end it articulates with the acromion 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<unk>  curves laterally and posteriorly for roughly half its length. It then forms a smooth posterior curve to articulate with a process of the scapula (acromion). The flat, acromial end of the<unk>  is broader than the sternal end. The acromial end has a rough inferior surface that bears prominent lines and tubercles. These surface features are attachment sites for muscles and ligaments of the shoulder.
Clavicle
Dermatophyte
Slug
Spore
Biofilm
Sponge
Speculum
Boil