Ulna


Ulna

Infobox Bone
Name = Ulna
Latin =
GraySubject = 52
GrayPage = 214


Caption = Upper extremity



Caption2 = Ulna is #2
Articulations =
MeshName = Ulna
MeshNumber = A02.835.232.087.090.850
DorlandsPre = u_01
DorlandsSuf = 12835497
The ulna (elbow bone) is a long bone, prismatic in form, placed at the medial side of the forearm, parallel with the radius.

Articulations

The ulna articulates with:
* the humerus, at the right side elbow as a hinge joint.
* the radius, near the elbow as a pivot joint, this allows the radius to cross over the ulna in pronation.
* the distal radius, where it fits into the ulna notch.
* the radius along its length via the interosseous membrane that forms a syndesmoses joint.

Proximal and distal aspects

The ulna is broader "proximally", and narrower "distally".

Proximally, the ulna has a bony process, the olecranon process, a hook-like structure that fits into the olecranon fossa of the humerus. This prevents hyperextension and forms a hinge joint with the trochlea of the humerus.There is also a radial notch for the head of the radius, and the ulnar tuberosity to which muscles can attach.

Distally (near the hand), there is a styloid process.

Structure

The long, narrow medullary cavity is enclosed in a strong wall of compact tissue which is thickest along the interosseous border and dorsal surface.

At the extremities the compact layer thins.

The compact layer is continued onto the back of the olecranon as a plate of close spongy bone with lamellæ parallel.

From the inner surface of this plate and the compact layer below it trabeculæ arch forward toward the olecranon and coronoid and cross other trabeculæ, passing backward over the medullary cavity from the upper part of the shaft below the coronoid.

Below the coronoid process there is a small area of compact bone from which trabeculæ curve upward to end obliquely to the surface of the semilunar notch which is coated with a thin layer of compact bone.

The trabeculæ at the lower end have a more longitudinal direction.

Muscle attachments

See also

*Bone terminology
*Terms for anatomical location
*Ossification of ulna


=Additional

External links

* [http://www.aofoundation.org/wps/portal/surgeryskully Ulnar fractures]


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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


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