STERNUM
Sternum
The sternum or breastbone, in vertebrate anatomy, is a flat bone that lies in the middle front part of the rib cage. It is endochondral in origin. It probably first evolved in early tetrapods as an extension of the pectoral girdle; it is not found in fish. In amphibians and reptiles it is typically a shield-shaped structure, often composed entirely of cartilage. It is absent in both turtles and snakes. In birds it is a relatively large bone and typically bears an enormous projecting keel to which the flight muscles are attached. Only in mammals does the sternum take on the elongated, segmented form seen in humans. In some mammals, such as ...The above text is a snippet from Wikipedia: Sternum
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sternum
Noun
- The breastbone.
The above text is a snippet from Wiktionary: sternum
and as such is available under the Creative Commons Attribution/Share-Alike License.