sternum

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A flat bone in the anterior midline of the thorax. The sternum consists of three parts: the manubrium at the top, the main sternal body, and the xiphoid process at the bottom.

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The breastbone, a median segmented skeletal structure made up of several elements or sternebrae, often with a considerable portion remaining cartilaginous into adulthood. It articulates with the cartilages of the sternal ribs and clavicles when large. It has three parts, the manubrium, the body and the xiphoid process, and consists of vascular, spongy bone covered with a thin layer of compact bone. In ruminants it has a flat ventral surface, while in horses it bears a keel (carina). It is especially well developed, as a nonsegmented keeled bone, in flying birds.

• inherited short s. — in the North Country Cheviot breed; characterized by a heavy mortality in newborn lambs resulting from rupture of the liver; the latter thought to occur because of the exposed position of the liver as a result of the absence of the sternum.

The elongated, flattened bone forming the middle portion of the thorax. It supports the clavicles and articulates directly with the first seven pairs of ribs.

• Trunk - sternum: flat bone of upper chest connecting ribs to shoulder girdle; breastbone
• Skeleton - sternum: breastbone

This article is about the vertebrate sternum in general. For other uses, see Human sternum and Sternum (arthropod anatomy).

The sternum or breastbone, in vertebrate anatomy, is a flat bone. 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.^[1] Only in mammals does the sternum take on the elongated, segmented form seen in humans. In some mammals, such as opossums, the individual segments never fuse and remain separated by cartilagenous plates throughout life.^[1]

References

1. ^ ^{a b} Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 188. ISBN 0-03-910284-X. 

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Dansk (Danish)
n. - brystben

Nederlands (Dutch)
borstbeen

Français (French)
n. - sternum

Deutsch (German)
n. - Brustbein

Ελληνική (Greek)
n. - (ανατ.) στέρνο

Italiano (Italian)
sterno

Português (Portuguese)
n. - esterno (m) (Anat.) (Zool.)

Русский (Russian)
грудина

Español (Spanish)
n. - esternón

Svenska (Swedish)
n. - bröstben

中文（简体）(Chinese (Simplified))
胸骨, 胸板, 胸片

中文（繁體）(Chinese (Traditional))
n. - 胸骨, 胸板, 胸片

한국어 (Korean)
n. - 흉골, 흉판, 복판

日本語 (Japanese)
n. - 胸骨, 腹板

العربيه (Arabic)
‏(الاسم) العظمه الوسطى في الصدر, القص‏

עברית (Hebrew)
n. - ‮עצם-החזה‬