Sternum

ster·num   (stûr'nəm)    n.   pl. ster·nums or ster·na (-nə) A long flat bone in most vertebrates that is situated along the ventral midline of the thorax and articulates with the ribs. The manubrium of the sternum articulates with the clavicles in humans and certain other vertebrates. Also called breastbone. [New Latin, from Greek sternon, breast, breastbone; see ster-2 in Indo-European roots.]

sternum 

Main Entry: ster·num
Pronunciation: 'st&r-n&m
Function: noun
Inflected Form: plural ster·nums or ster·na /-n&/
: a compound ventral bone or cartilage that lies in the median central part of the body of most vertebrates above fishes and that in humans is about seven inches (18centimeters) long, consists in the adult of three parts, and connects with the clavicles and the cartilages of the upper seven pairs of ribs called also breastbone

sternum ster·num (stûr'nəm)
n. pl. ster·nums or ster·na (-nə)
A long flat bone, articulating with the cartilages of the first seven ribs and with the clavicle, forming the middle part of the anterior wall of the thorax, and consisting of the corpus, manubrium, and xiphoid process. Also called breastbone.

sternum

in the anatomy of tetrapods (four-limbed vertebrates), elongated bone in the centre of the chest that articulates with and provides support for the clavicles (collarbones) of the shoulder girdle and for the ribs. Its origin in evolution is unclear. A sternum appears in certain salamanders; it is present in most other tetrapods but lacking in legless lizards, snakes, and turtles (in which the shell provides needed support). In birds an enlarged keel develops, to which flight muscles are attached; the sternum of the bat is also keeled as an adaptation for flight

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