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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 Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



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 Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


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
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Multiple small lytic areas involving predominantly upper part of sternum with associated soft tisue external and internal components.
sternum II (posterior edge) and III (anterior edge) as 2+2 and 1+1 modified chaetae, dorsal pso formula: 42/022/33332 P.
Of the 62 pedestrians who succumbed to death, 25 persons (21.8%) had fracture of sternum. Side seat occupants had only 1.8% of sternum fracture.
Mrs Steele was in hospital for some time with a fractured neck, spine, and sternum.
It showed that as well as a fracture to the end of my sternum I had a small liver tear and bruising to my pancreas, none of which required surger y.
After 10 weeks off, Zanotti competed successfully at Snetterton in the middle of June, and had no problems in the session leading up to the Knockhill race, but said the extremely physical nature of the Scottish circuit finally took its toll, putting extreme pressure on the healed break in his sternum.
(3,4) Sternum remains the most common site to be involved, though rib shafts, costochondral junctions, and vertebral bodies can also be involved.
The furcula (clavicles) is fused to the most cranial and ventral aspect of the sternum. There is a nonfusion of the caudal third of the sternum.
Caroline Buchanan, a five-time mountain bike world champion who has also won the BMX world title three times, said her lungs had collapsed and she had broken her sternum and nose in a car crash.
Other symptoms to watch out for include a painful tummy or sternum, feeling full after eating small amounts of food, and a burning sensation when swallowing.
Only two to ten per cent of bone tumours occur in the chest wall and only 20 per cent of these occur in the sternum; however, when they do occur, they are generally malignant.
The condition causes her sternum and rib cage to protrude outwards as she grows.