AskDefine | Define elbow

Dictionary Definition

elbow

Noun

1 hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped [syn: elbow joint, cubitus, cubital joint, articulatio cubiti]
2 a sharp bend in a road or river
3 a length of pipe with a sharp bend in it
4 the part of a sleeve that covers the elbow; "his coat had patches over the elbows"
5 the joint of a mammal or bird that corresponds to the human elbow

Verb

1 push one's way with the elbows
2 shove one's elbow into another person's ribs

User Contributed Dictionary

English

Etymology

elnboga, from Germanic, corresponding to ell + bow. Cognate with Dutch elleboog, German Ellbogen.

Pronunciation

  • (UK) /ˈɛlbəʊ/
  • (US) /ˈɛlboʊ/

Noun

  1. The joint between the upper arm and the forearm.
  2. A pipe fitting that turns a corner.

Derived terms

Translations

joint between upper arm and forearm
pipe fitting
  • Finnish: mutka
  • Russian: колено

Verb

  1. To push with the elbow; to jostle or force.
    He elbowed his way through the crowd.

Extensive Definition

The elbow-joint is a ginglymus or hinge joint. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm.
The elbow is the region surrounding the elbow-joint.
The bony prominence at the very tip of the elbow is the olecranon process of the ulna, and the inner aspect of the elbow is called the antecubital fossa.

Movements

Two main movements are possible at the elbow:
  • The hinge-like bending and straightening of the elbow (flexion and extension) happens at the articulation ("joint") between the humerus and the ulna.
  • The complex action of turning the forearm over (pronation or supination) happens at the articulation between the radius and the ulna (this movement also occurs at the wrist joint).
In the anatomical position (with the forearm supine), the radius and ulna lie parallel to each other. During pronation, the ulna remains fixed, and the radius rolls around it at both the wrist and the elbow joints. In the prone position, the radius and ulna appear crossed.
Most of the force through the elbow joint is transferred between the humerus and the ulna. Very little force is transmitted between the humerus and the radius. (By contrast, at the wrist joint, most of the force is transferred between the radius and the carpus, with the ulna taking very little part in the wrist joint).

Muscles, arteries, and nerves

The muscles in relation with the joint are:
The arteries supplying the joint are derived from the anastomosis between the profunda and the superior and inferior ulnar collateral branches of the brachial, with the anterior, posterior, and interosseous recurrent branches of the ulnar, and the recurrent branch of the radial. These vessels form a complete anastomotic network around the joint.
The nerves of the joint are a twig from the ulnar, as it passes between the medial condyle and the olecranon; a filament from the musculocutaneous, and two from the median.

Portions of joint

The elbow-joint comprises three different portions. All these articular surfaces are enveloped by a common synovial membrane, and the movements of the whole joint should be studied together.
The combination of the movements of flexion and extension of the forearm with those of pronation and supination of the hand, which is ensured by the two being performed at the same joint, is essential to the accuracy of the various minute movements of the hand.
The hand is only directly articulated to the distal surface of the radius, and the ulnar notch on the lower end of the radius travels around the lower end of the ulna. The ulna is excluded from the wrist-joint by the articular disk.
Thus, rotation of the head of the radius around an axis passing through the center of the radial head of the humerus imparts circular movement to the hand through a very considerable arc.

Ligaments

The trochlea of the humerus is received into the semilunar notch of the ulna, and the capitulum of the humerus articulates with the fovea on the head of the radius. The articular surfaces are connected together by a capsule, which is thickened medially and laterally, and, to a less extent, in front and behind. These thickened portions are usually described as distinct ligaments.

Synovial membrane

The synovial membrane is very extensive. It extends from the margin of the articular surface of the humerus, and lines the coronoid, radial and olecranon fossæ on that bone; it is reflected over the deep surface of the capsule and forms a pouch between the radial notch, the deep surface of the annular ligament, and the circumference of the head of the radius. Projecting between the radius and ulna into the cavity is a crescentic fold of synovial membrane, suggesting the division of the joint into two; one the humeroradial, the other the humeroulnar.
Between the capsule and the synovial membrane are three masses of fat:
  • the largest, over the olecranon fossa, is pressed into the fossa by the Triceps brachii during the flexion;
  • the second, over the coronoid fossa,
  • and the third, over the radial fossa, are pressed by the Brachialis into their respective fossæ during extension.

Terminology: "Elbow" and "Ell"

The now obsolete length unit ell relates closely to the elbow. This becomes especially visible when considering the Germanic origins of both words, Elle (ell, defined as the length of an arm from shoulder to fingertips) and Ellbogen (elbow).
It is unknown when or why the second "l" was dropped from English usage of the word, but a more precise suggested spelling would be "ellbow" for the joint and "ellbone" for the ulna, the etymological originator of both unit and joint.

Carrying angle

When the arm is extended, with the palm facing forward or up, the bones of the humerus and forearm are not perfectly aligned. The deviation from a straight line (generally on the order of 5-10°-men, 10-25°-women) occurs in the direction of the thumb, and is referred to as the carrying angle (visible in the right half of the picture, right). In females the carrying angle is greater than in males.
Carrying angle is typically larger in women than in men, due to the wider pelvic girdle exhibited in women.
The carrying angle can influence how objects are held by individuals - those with a more extreme carrying angle may be more likely to supinate the forearm when holding objects in the hand to keep the elbow closer to the body.

Elbow arthritis

Elbow arthritis is usually seen in individuals with rheumatoid arthritis or after severe articular fractures. When the damage to the joint is severe, fascial arthroplasty or elbow joint replacement may be considered.

Additional images

Image:MedialHumerusRadiusUlnaArticulated.jpg.jpg|Medial Humerus Radius Ulna Articulated Image:Elbow by David Shankbone.jpg|Left male elbow Image:Pathological fusion of three bones at elbow.jpg|Pathological fusion of three bones at elbow.

References

elbow in Arabic: مرفق
elbow in Aymara: Mujlli
elbow in Catalan: Colze
elbow in Danish: Albue
elbow in German: Ellbogengelenk
elbow in Spanish: Codo (anatomía)
elbow in Esperanto: Kubuto
elbow in French: Coude (anatomie)
elbow in Scottish Gaelic: Uilinn
elbow in Indonesian: Siku
elbow in Italian: Gomito
elbow in Hebrew: מרפק
elbow in Latin: Cubitus (anatomia)
elbow in Hungarian: Könyök
elbow in Dutch: Elleboog
elbow in Japanese: 肘
elbow in Norwegian: Albue
elbow in Polish: Staw łokciowy
elbow in Portuguese: Cotovelo
elbow in Simple English: Elbow
elbow in Slovenian: Komolec
elbow in Finnish: Kyynärpää
elbow in Swedish: Armbågsled
elbow in Tagalog: Siko
elbow in Thai: ข้อศอก
elbow in Turkish: Dirsek
elbow in Võro: Künnärpää
elbow in Yiddish: עלנבויגן

Synonyms, Antonyms and Related Words

L, angle, angle off, ankle, apex, arm, articulation, assault, barge in, bear, bear upon, bend, biceps, bifurcate, bifurcation, bight, boost, boundary, branch, break in, break in upon, buck, bull, bulldoze, bump, bump against, bunt, burst in, butt, butt against, butt in, cant, cervix, charge in, chevron, clinch, closure, coin, come between, connecting link, connecting rod, connection, corner, coupling, cram, crank, crash, crash in, crash the gates, creep in, crook, crotchet, crowd, crowd in, cut in, deflection, dig, dogleg, dovetail, drive, edge in, elbow in, ell, embrace, encroach, entrench, foist in, force, forearm, fork, furcate, furcation, gliding joint, goad, hinge, hinged joint, hip, hook, horn in, hurtle, hustle, impinge, impose, impose on, impose upon, infiltrate, inflection, infringe, insinuate, interface, interfere, interlope, interpose, intervene, intrude, invade, irrupt, jab, jam, jog, joggle, join, joining, joint, jolt, jostle, juncture, knee, knuckle, link, miter, mortise, neck, nook, nudge, obtrude, pile drive, pivot, pivot joint, point, poke, press, press in, prod, punch, push, push in, put on, put upon, quoin, rabbet, ram, ram down, rattle, run, run against, rush in, scarf, seam, shake, shoulder, shove, slink in, slip in, smash in, sneak in, squeeze in, steal in, stitch, storm in, stress, suture, swerve, symphysis, tamp, throng in, thrust, thrust in, tie rod, toggle, toggle joint, trench, trespass, union, upper arm, veer, vertex, weld, work in, worm in, wrist, zag, zig, zigzag
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