Definition of Breast bone

Breast bone: Familiar name for the sternum, the long flat bone in the middle of the front of the chest.

The sternum consists of three portions: the manubrium (the upper segment of the sternum, a flattened, roughly triangular bone), the corpus or body of the sternum, and the xiphoid process (the little tail of the sternum than points down). These three portions of the sternum arise as separate bones and may fuse partially or completely with one another.

The sternum articulates (makes contact) with the cartilages of the first seven ribs and the clavicles (the collar bones) to form the middle portion of the anterior front wall of the thorax.