sternum


sternum
/sterr"neuhm/, n., pl. sterna /-neuh/, sternums.
1. Anat., Zool. a bone or series of bones extending along the middle line of the ventral portion of the body of most vertebrates, consisting in humans of a flat, narrow bone connected with the clavicles and the true ribs; breastbone. See diag. under skeleton.
2. the ventral surface of a body segment of an arthropod.
[1660-70; < NL < Gk stérnon chest, breastbone]

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also called  breastbone 

      in the anatomy of tetrapods (four-limbed vertebrates), elongated bone in the centre of the chest (thorax) that articulates with and provides support for the clavicles (clavicle) (collarbones) of the shoulder girdle and for the ribs. Its origin in evolution is unclear. A sternum appears in certain salamanders; it is present in most other tetrapods but lacking in legless lizards, snakes, and turtles (in which the shell provides needed support). In birds an enlarged keel develops, to which flight muscles are attached; the sternum of the bat is also keeled as an adaptation for flight.

      In mammals the sternum is divided into three parts, from anterior to posterior: (1) the manubrium, which articulates with the clavicles and first ribs; (2) the mesosternum, often divided into a series of segments, the sternebrae, to which the remaining true ribs are attached; and (3) the posterior segment, called the xiphisternum. In humans the sternum is elongated and flat; it may be felt from the base of the neck to the pit of the abdomen. The manubrium is roughly trapezoidal, with depressions where the clavicles and the first pair of ribs join. The mesosternum, or body, consists of four sternebrae that fuse during childhood or early adulthood. The mesosternum is narrow and long, with articular facets for ribs along its sides. The xiphisternum is reduced to a small, usually cartilaginous xiphoid (“sword-shaped”) process. The sternum ossifies from several centres. The xiphoid process may ossify and fuse to the body in middle age; the joint between manubrium and mesosternum remains open until old age.

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Universalium. 2010.

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  • sternum — [ stɛrnɔm ] n. m. • 1555; lat. méd., gr. sternon ♦ Os plat, allongé, situé au milieu de la face antérieure du thorax, s articulant avec les sept premières paires de côtes et, par son segment supérieur (⇒ manubrium), avec les deux clavicules.… …   Encyclopédie Universelle

  • Sternum — Ster num, n.; pl. L. {Sterna}, E. {Sternums}. [NL., from Gr. ?, the breast, chest.] 1. (Anat.) A plate of cartilage, or a series of bony or cartilaginous plates or segments, in the median line of the pectoral skeleton of most vertebrates above… …   The Collaborative International Dictionary of English

  • Sternum — (lat., v. gr.), s. Brustbein …   Pierer's Universal-Lexikon

  • Sternum — (lat.), das Brustbein …   Meyers Großes Konversations-Lexikon

  • Sternum — (lat.), das Brustbein (s. Brust) …   Kleines Konversations-Lexikon

  • Sternum — Sternum, lat., das Brustbein …   Herders Conversations-Lexikon

  • Sternum — Sternum, 1) Brustbein der Wirbeltiere; 2) ventraler Bereich eines Segments des Insektenkörpers …   Deutsch wörterbuch der biologie

  • sternum — 1660s, from Gk. sternon chest, breast, breastbone (in Homer, only of males), from PIE *stre to to stretch, extend, from a root meaning flat surface, related to stornynai to spread out (see STRUCTURE (Cf. structure)), on the notion of the chest as …   Etymology dictionary

  • sternum — stèrnum m DEFINICIJA anat. široka, plosnata kost, s prednje strane zatvara prsni koš i spaja prednje krajeve gornjih 7 rebara; prsna kost ETIMOLOGIJA nlat. ← grč. stérnon: prsa …   Hrvatski jezični portal

  • sternum — ► NOUN (pl. sternums or sterna) ▪ the breastbone. ORIGIN Greek sternon chest …   English terms dictionary

  • sternum — [stʉr′nəm] n. pl. sternums or sterna [ModL < Gr sternon, the breastbone < IE base * ster , to spread out, STREW] a thin, flat structure of bone and cartilage to which most of the ribs are attached in the front of the chest in most… …   English World dictionary


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