Elbow
321837
225674925
2008-07-14T21:07:39Z
Iridescent
937705
Cleanup/[[WP:AWB/T|typo fixing]], typos fixed: greek → Greek using [[Project:AutoWikiBrowser|AWB]]
{{two other uses||the band|Elbow (band)}} {{Refimprove|date=June 2008}}
{{Infobox Anatomy |
Name = Elbow-joint |
Latin = articulatio cubiti |
GraySubject = 84 |
GrayPage = 321 |
Image = Elbow_coude.JPG|
Caption = Elbow |
Image2 = Gray329.png |
Caption2 = Left elbow-joint, showing anterior and ulnar collateral ligaments. |
Precursor = |
System = |
Artery = |
Vein = |
Nerve = |
Lymph = |
MeshName = Elbow+joint |
MeshNumber = A02.835.583.290 |
DorlandsPre = a_64 |
DorlandsSuf = 12161185 |
}}
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 (bone)|radius]] and [[ulna]] of the forearm.<ref>[http://www.emedicine.com/asp/dictionary.asp?keyword=Elbow+joint eMedicine/Stedman Medical Dictionary Lookup!<!-- Bot generated title -->]</ref>
The '''elbow''' is the region surrounding the elbow-joint.<ref>[http://www.emedicine.com/asp/dictionary.asp?keyword=Elbow eMedicine/Stedman Medical Dictionary Lookup!<!-- Bot generated title -->]</ref>
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 ([[anatomical terms of motion|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 [[muscle]]s in relation with the joint are:
* in ''front,'' the [[Brachialis]]
* ''behind,'' the [[Triceps brachii]] and [[Anconæus]]
* ''laterally,'' the [[Supinator]], and the common tendon of origin of the Extensor muscles
* ''medially,'' the common tendon of origin of the Flexor muscles, and the [[Flexor carpi ulnaris]]
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 nerve|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.
{| class="wikitable"
| '''Joint''' || '''From''' || '''To''' || '''Description'''
|-
| [[humeroulnar joint]] || [[trochlear notch]] of the [[ulna]] || [[trochlea of humerus]] || Is a simple [[hinge-joint]], and allows of movements of flexion and extension only.
|-
| [[humeroradial joint]] || [[head of the radius]] || [[capitulum of the humerus]] || Is an [[arthrodial]] joint.
|-
| [[proximal radioulnar joint]] || [[head of the radius]] || [[radial notch]] of the [[ulna]] || In any position of flexion or extension, the radius, carrying the hand with it, can be rotated in it. This movement includes [[pronation]] and [[supination]].
|}
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 (bone)|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.
The major ligaments are the [[ulnar collateral ligament (elbow)|ulnar collateral ligament]], [[radial collateral ligament (elbow)|radial collateral ligament]], and [[annular ligament]].
== 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" , "Ell" And "Weinus" ==
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.
The elbow has also been called the weinus (wee-nus), it has been declared the scientific term for the ligament. The word forms from the Greek translation of weinu meaning movement back and forth.
==Carrying angle==
[[Image:Coude fp.PNG|Normal radiograph; right picture of the straightened arm shows the carrying angle of the elbow|thumb]]
When the arm is [[Extension (kinesiology)|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.<ref>{{cite journal | last = Steel | first = F | coauthors = Tomlinson J | title = The carrying angle in man | journal = Journal of Anatomy | volume = 92 | issue = 2 | pages = 315–7 | year = 1958 | pmid = 13525245 | url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1249704 }}</ref>
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 [[supination|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.<ref>[http://www.orthop.washington.edu/elbowreplacement Summary - Total elbow joint replacement for elbow arthritis: Surgery with a dependable, time-tested prosthesis can lessen pain and improve function in elbows, especially those with rheumatoid arthritis<!-- Bot generated title -->]</ref>
==Additional images==
<gallery>
Image:MedialHumerusRadiusUlnaArticulated.jpg.jpg|Medial Humerus Radius Ulna Articulated
Image:LeftHumanPosteriorDistalHumerusExtended.jpg|Left Human Posterior Distal Humerus Extended
Image:LeftHumanPosteriorDistalHumerusFlexed.jpg|Left Human Posterior Distal Humerus Flexed
Image:Gray330.png|Left elbow-joint, showing posterior and radial collateral ligaments.
Image:Gray331.png|Capsule of elbow-joint (distended). Anterior aspect.
Image:Gray332.png|Capsule of elbow-joint (distended). Posterior aspect.
Image:Gray420.png|The Supinator. Posterior view.
Image:Gray526.png|Diagram of the anastomosis around the elbow-joint.
Image:Gray1232.png|Back of right upper extremity.
Image:RightElbowXray.jpg|Close-up radiograph, right elbow-joint
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.
</gallery>
==References==
<references/>
{{wiktionary|Elbow}}
{{Gray's}}
{{human anatomical features}}
{{Joints of upper limbs}}
[[Category:Upper limb anatomy]]
[[ar:مرفق]]
[[ay:Mujlli]]
[[br:Ilin]]
[[ca:Colze]]
[[cs:Loket (část těla)]]
[[da:Albue]]
[[de:Ellbogengelenk]]
[[es:Codo]]
[[eo:Kubuto]]
[[fr:Coude (anatomie)]]
[[gd:Uilinn]]
[[id:Siku]]
[[it:Gomito]]
[[he:מרפק]]
[[la:Cubitus (anatomia)]]
[[hu:Könyök]]
[[nl:Elleboog]]
[[ja:肘]]
[[no:Albue]]
[[pl:Staw łokciowy]]
[[pt:Cotovelo]]
[[simple:Elbow]]
[[sl:Komolec]]
[[fi:Kyynärpää]]
[[sv:Armbågsled]]
[[tl:Siko]]
[[te:మోచేయి]]
[[th:ข้อศอก]]
[[tr:Dirsek]]
[[fiu-vro:Künnärpää]]
[[yi:עלנבויגן]]