Stēr'num, n.

n. [N. Lat., from Gr. στέρενον. See STERNON.] (Anat.) A flat, symmetrical bone on the median line of the chest in front, articulated with the clavicles and the cartilages of the upper seven ribs.

¶ In birds, it is the large bone of the breast, corresponding to a coalesced series of hæmal spines. In the turtle, it consists of nine pieces, the middle one called entosternal or entosternum, and the four remaining pairs, severally, episternal, hyosternal, hyposternal, and xiphisternal. There is rarely another pair, called mesosternal. R. Owen.