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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 ?
11, that the GSK-3ss protein participates in palate development and breastbone formation at different times.
Normally, to reach a failing heart, surgeons must saw through the breastbone and crack open ribs.
Then, from the top of the bird, cut between the breastbone and the meat along the length of the breast, angling the knife down, parallel to the carcass, to meet the first cut.
Circulation - check for pulse; if there isn't one take the heel of both hands and press down on the breastbone at a rate of one compression a second; continue until paramedics arrive.
As soon as the breastbone is reached, drop the point just beneath and pass it under the breastbone.
The chest pain, which is caused by reduced blood flow to the heart, typically occurs behind the breastbone and may travel down your left arm or up your neck, or be a squeezing, pressing sensation that does not change with breathing.
The most common ulcer symptom is a gnawing or burning pain in the abdomen between the breastbone and the naval.
He was pleased to find that the heart sounds were actually louder than they would have been if he had placed his ear directly to the breastbone.
Peter Maggs, from Abergavenny, had three ribs and half his breastbone removed during a day-long operation to take out a tumour the size of a tennis ball.
STEP 4: Giving chest compressions | Kneel down beside the casualty on the floor, level with their chest | Place the heel of one hand towards the end of their breastbone, in the centre of their chest | Place the heel of your other hand on top of the first hand and interlock your fingers, making sure you keep the fingers off the ribs | Lean over the casualty, with your arms straight, pressing down vertically on the breastbone, and press the chest down by 5-6cm (2-21/2in) | Release the pressure without removing your hands from their chest.
In open-heart surgery, the surgeon cuts through the breastbone, stops the heart, removes the valve and replaces it.