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see ribrib,
one of the slender, elongated, curved bones that compose the chest cage in higher vertebrates. Ribs occur in pairs, and are found in most vertebrates; however, in some lower vertebrates, including fishes, they run along the entire length of the backbone.
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the complex of skeletal elements in terrestrial vertebrates and man that unite, along the midline of the body, the ventral ends of the true ribs and parts of the pectoral girdle and to which the sternal muscles are attached.

The sternum is a derivative of the ribs and first appeared in terrestrial vertebrates when a strengthening of support for the pectoral girdle was required in connection with the progressive evolution of the forelimbs. In amphibians and reptiles the sternum is usually cartilaginous; in the latter, only a few ribs are attached, forming the thorax. In birds the sternum is osseous; in flying birds there is a median process, the keel, to which the powerful pectoral muscles are attached. In mammals the sternum consists of three sections: the manubrium, the corpus sterni, and the xiphoid process. In man the sternum, or breastbone, is an unpaired flat bone that forms the middle part of the anterior wall of the thorax.


The bone, cartilage, or series of bony or cartilaginous segments in the median line of the anteroventral part of the body of vertebrates above fishes, connecting with the ribs or pectoral girdle.


1. (in man) a long flat vertical bone, situated in front of the thorax, to which are attached the collarbone and the first seven pairs of ribs
2. the corresponding part in many other vertebrates
3. a cuticular plate covering the ventral surface of a body segment of an arthropod
References in periodicals archive ?
Charlotte Milsom with her daughter Layla Grace, who was born with a condition which causes her sternum and rib cage to protrude outwards
To assess the correlation between transcutaneous bilirubinometer readings at different sites (Forehead, sternum and pubic symphysis) with serum bilirubin levels and to determine the diagnostic value of transcutaneous bilirubinometer in evaluating pathologic jaundice by calculating sensitivity, specificity, positive predictive value and negative predictive value.
During reduction mammoplasty, reattaching the skin envelope to the sternum to re-establish the medial border of the breast can be done with several subdermal sutures.
The front of the girdle is composed of the sternum in the middle and the two clavicles on either side.
Niall Hannity, a friend of Maguire, last night said: "He has fractured his sternum and has bleeding on his liver.
Initial inspection of the mass showed that it was stuck to the posterior of the sternum and the left sternoclavicular joint.
In a statement read to the court, Dr Bolton said: "The chest injury completely cut through the sternum from front to back and side to side.
But cardiac surgeons today often incise two-thirds of the sternum rather than its entire length, which makes healing even easier.
There were no signs of ecchymosis or swelling over the sternum, while tenderness over the body of the sternum was present.
Ambulance crews said one 18-year-old suffered a sternum injury and a man in his 20s sustained head and neck injuries.
colombiensis), the presence of a deep concave U-shaped medioapical notch on metasomal sternum V (such a notch absent in C.