ulna


ulna
ulnar, adj.
/ul"neuh/, n., pl. ulnae /-nee/, ulnas.
1. Anat. the bone of the forearm on the side opposite to the thumb. Cf. radius (def. 7). See diag. under skeleton.
2. a corresponding bone in the forelimb of other vertebrates.
[1835-45; < L: elbow; akin to Gk oléne, OE eln ELL2]

* * *

 inner of two bones (bone) of the forearm when viewed with the palm facing forward. (The other, shorter bone of the forearm is the radius.) The upper end of the ulna presents a large C-shaped notch—the semilunar, or trochlear, notch—which articulates with the trochlea of the humerus (upper arm bone) to form the elbow joint. The projection that forms the upper border of this notch is called the olecranon process; it articulates behind the humerus in the olecranon fossa and may be felt as the point of the elbow. The projection that forms the lower border of the trochlear notch, the coronoid process, enters the coronoid fossa of the humerus when the elbow is flexed. On the outer side is the radial notch, which articulates with the head of the radius. The head of the bone is elsewhere roughened for muscle attachment. The shaft is triangular in cross section; an interosseous ridge extends its length and provides attachment for the interosseous membrane connecting the ulna and the radius. The lower end of the bone presents a small cylindrical head that articulates with the radius at the side and the wrist bones below. Also at the lower end is a styloid process, medially, that articulates with a disk between it and the cuneiform (os triquetrum) wrist bone.

 The ulna is present in all land vertebrates. In amphibians (amphibian) and some reptiles (reptile) the radius and ulna do not articulate. The elbow joint evolved first among birds (bird) and mammals (mammal). The radius tends to be slender in birds; but the ulna is more often reduced in mammals, especially in those adapted for running and, in the case of bats, flying.
 

* * *


Universalium. 2010.

Look at other dictionaries:

  • ulnă — ÚLNĂ s. v. cubitus. Trimis de siveco, 13.09.2007. Sursa: Sinonime  ÚLNĂ s.f. Cubitus. [< lat. ulna]. Trimis de LauraGellner, 13.09.2007. Sursa: DN  ÚLNĂ s. f. cubitus. (< lat. ulna) Trimis …   Dicționar Român

  • ULNA — ex Graeco ὠλένη, proprie brachium, cubitus. Calpurnius, Ecl. 1. v. 45. de Numeriano Caes. maternis causas qui lusit in ulnis. Unde tendere ulnas, dicit Statius, l. 10. Theb. v. 515. pronas tendentis Amyntoris ulnas Fundentisque preces Quomodo… …   Hofmann J. Lexicon universale

  • ulna — s.f. [dal lat. ulna, dal gr. ōlénē cubito, braccio ]. (anat.) [osso lungo pari che insieme con il radio costituisce lo scheletro dalla parte intermedia dell arto anteriore dei tetropodi] ▶◀ cubito …   Enciclopedia Italiana

  • ulna — s. f. 1.  [Anatomia] O mesmo que cúbito. 2.  [Antigo] Medida equivalente a uma braça.   ‣ Etimologia: latim ulna, ae, cotovelo …   Dicionário da Língua Portuguesa

  • ulna — ȗlna ž DEFINICIJA anat. duga cjevasta kost podlaktice; lakatna kost ETIMOLOGIJA lat. ulna …   Hrvatski jezični portal

  • Ulna — Ul na, n. [L., the elbow. See {Ell}.] 1. (Anat.) The postaxial bone of the forearm, or branchium, corresponding to the fibula of the hind limb. See {Radius}. [1913 Webster] 2. (O. Eng. Law) An ell; also, a yard. Burrill. [1913 Webster] …   The Collaborative International Dictionary of English

  • Ulna — (lat.), 1) so v.w. Ellenbogenknochen, s.u. Armknochen C); 2) Elle, die Länge des Arms od. 2 Fuß betragend …   Pierer's Universal-Lexikon

  • Ulna — (lat.), Elle, s. Arm …   Meyers Großes Konversations-Lexikon

  • Ulna — (lat.), Ellbogenbein (s. Ellbogen); ulnār, was sich auf U. bezieht …   Kleines Konversations-Lexikon

  • ulna — ● ulna nom féminin (mot latin signifiant avant bras) Cubitus …   Encyclopédie Universelle

  • Ulna — Ulna, Elle ⇒ Zeugopodium …   Deutsch wörterbuch der biologie


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.