The Collar bone reference article from the English Wikipedia on 24-Apr-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Collar bone

Sponsor with the world's largest charity for orphans
In anatomy, the clavicle or collar bone is a bone located in the chest wall anterior and superior to the lungs.

It articulates with the sternum medially and the acromion, part of the scapula, laterally. It is part of the shoulder girdle and together with the scapula, allows for the free range of motion of the arms. Compare this with the limited range of motion of the legs.