Forearm
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219450585
2008-06-15T08:08:52Z
KC Panchal
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/* Muscles */ corrected the spelling of supination
{{Refimprove|article|date=December 2007}}
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = antebrachium |
GraySubject = |
GrayPage = |
Image = Forearm labeled.png |
Caption = Upper limb, forearm pronated. The forearm is the part of the [[upper limb]] between the [[Elbow-joint|elbow]] and the [[wrist]]. |
Width = 100px|
Image2 = |
Caption2 = |
Precursor = |
System = |
Artery = |
Vein = |
Nerve = |
Lymph = |
MeshName = Forearm |
MeshNumber = A01.378.800.585 |
DorlandsPre = a_45 |
DorlandsSuf = 12138967 |
}}
{{For|the firearm component|Forearm (firearm component)}}
The '''forearm''' is the structure on the [[upper limb]], between the [[Elbow-joint|elbow]] and the [[wrist]].<ref>{{eMedicineDictionary|Forearm}}</ref>. This term is used in [[anatomy]] to distinguish it from the arm (or upper arm). It is [[:Wiktionary:homologous|homologous]] to the [[leg]] that lies between the [[knee]] and the [[ankle]] joints.
==The human forearm==
The forearm contains two long [[bone]]s, the [[radius (bone)|radius]] and the [[ulna]], forming the '''radioulnar joint'''. The [[interosseous membrane]] connects these bones. Ultimately, the forearm is covered by skin, the anterior surface usually being less hairy than the posterior surface.
The forearm contains many muscles, including the flexors and extensors of the digits, a flexor of the elbow ([[brachioradialis]]), and pronators and supinators that turn the hand to face down or upwards, respectively. In cross-section the forearm can be divided into two [[fascial compartment]]s. The posterior compartment contains the extensors of the hands, which are supplied by the [[radial nerve]]. The anterior compartment contains the flexors, and is mainly supplied by the [[median nerve]]. The [[ulnar nerve]] also runs the length of the forearm.
The [[radial artery|radial]] and [[ulnar artery|ulnar arteries]], and their branches, supply the blood to the forearm. These usually run on the anterior face of the radius and ulna down the whole forearm. The main superficial veins of the forearm are the [[cephalic vein|cephalic]], [[median antebrachial vein|median antebrachial]] and the [[basilic vein]]. These veins can be used for cannularisation or [[venipuncture]], although the [[cubital fossa]] is a preferred site for getting blood.
==Anatomy==
===Bones===
*[[radius (bone)|radius]]
*[[ulna]]
===Joints===
*'''proximal to forearm'''
**[[elbow-joint|elbow]]
*'''in the forearm'''
**[[proximal radioulnar joint]]
**[[distal radioulnar joint]]
*''distal to forearm''
**[[wrist]]
===Muscles===
{{Seealso|Muscle table#Forearm}}
{| class="wikitable" class="sortable wikitable"
| '''Compartment''' || '''Level''' || '''Muscle''' || '''E/I''' || '''Nerve'''
|-
| Anterior || superficial || [[flexor carpi radialis]] || E || median
|-
| Anterior || superficial || [[palmaris longus]] || E || median
|-
| Anterior || superficial || [[flexor carpi ulnaris]] || E || ulnar
|-
| Anterior || superficial || [[pronator teres]] || I || median
|-
| Anterior || superficial (or intermediate) || [[flexor digitorum superficialis|flexor digitorum superficialis (sublimis)]] || E || median
|-
| Anterior || deep || [[flexor digitorum profundus]] || E || ulnar + median
|-
| Anterior || deep || [[flexor pollicis longus]] || E || median
|-
| Anterior || deep || [[pronator quadratus]] || I || median
|-
| Posterior || (see below) || [[brachioradialis]] || I || radial
|-
| Posterior || superficial || [[extensor carpi radialis longus]] || E || radial
|-
| Posterior || superficial || [[extensor carpi radialis brevis]] || E || radial
|-
| Posterior || intermediate || [[extensor digitorum|extensor digitorum (communis)]] || E || radial
|-
| Posterior || intermediate || [[extensor digiti minimi|extensor digiti minimi (proprius)]] || E || radial
|-
| Posterior || superficial || [[extensor carpi ulnaris]] || E || radial
|-
| Posterior || deep || [[abductor pollicis longus]] || E || radial
|-
| Posterior || deep || [[extensor pollicis brevis]] || E || radial
|-
| Posterior || deep || [[extensor pollicis longus]] || E || radial
|-
| Posterior || deep || [[extensor indicis|extensor indicis (proprius)]] || E || radial
|-
| Posterior || deep || [[supinator]] || I || radial
|-
| Posterior || deep || [[anconeus]] || I || radial
|}
* "E/I" refers to "extrinsic" or "intrinsic". The intrinsic muscles of the forearm act on the forearm, meaning, across the elbow joint and the [[Proximal radioulnar articulation| proximal]] and [[Distal radioulnar articulation| distal]] radioulnar joints (resulting in [[pronation]] or [[supination]], whereas the extrinsic muscles act upon the hand and wrist. In most cases, the extrinsic anterior muscles are ''flexors'', while the extrinsic posterior muscles are ''extensors''.
* The Brachioradialis, flexor of the forearm, is unusual in that it is located in the [[posterior compartment]], but it is actually in the anterior portion of the forearm.
===Nerves===
''(See separate nerve articles for details on divisions proximal to the elbow and distal to the wrist; see [[Brachial plexus]] for the origins of the median, radial and ulnar nerves)''
*[[Median nerve]] - principle nerve of the anterior compartment ([[pronator teres|PT]], [[Flexor carpi radialis|FCR]], [[Palmaris longus|PL]], [[Flexor digitorum superficialis|FDS]]).
**[[anterior interosseous nerve]] (supplies [[flexor pollicis longus|FPL]], lat. 1/2 of [[Flexor digitorum profundus|FDP]], [[pronator quadratus|PQ]]).
*[[Radial nerve]] - supplies muscles of the posterior compartment ([[Extensor Carpi Radialis Longus|ECRL]], [[Extensor Carpi Radialis Brevis|ECRB]]).
**[[Superficial branch of radial nerve]]
**[[Deep branch of radial nerve]], becomes [[Posterior interosseus nerve]] and supplies muscles of the posterior compartment ([[Extensor Digitorum|ED]], [[Extensor Digiti Minimi|EDM]], [[Extensor Carpi Ulnaris|ECU]], [[Abductor Pollicis Longus|APL]], [[Extensor Pollicis Brevis|EPB]], [[Extensor Pollicis Longus|EPL]], [[Extensor Indicis|EI]]).
*[[Ulnar nerve]] - supplies some medial muscles ([[Flexor Carpi Ulnaris|FCU]], med. 1/2 of [[Flexor Digitorum Profundus|FDP]]).
===Vessels===
{{Main|Arterial tree of subclavian artery}}
*[[brachial artery]]
**[[radial artery]]
***[[radial recurrent artery]]
**[[ulnar artery]]
***[[pulmonary artery]]
***[[anterior ulnar recurrent artery]] and [[posterior ulnar recurrent artery]]
***[[common interosseous artery]]
****[[posterior interosseous artery]]
****[[anterior interosseous artery]]
===Other structures===
*[[interosseous membrane of the forearm]]
*[[annular ligament]] of ulna
==Additional images==
<gallery>
Image:Gray414.png|Superficial muscles of the forearm
Image:Gray415.png|Deep muscles of the forearm
Image:Gray417_color.PNG|Cross-section through the middle of the forearm.
</gallery>
==References==
<references/>
== External links ==
* [http://www.aofoundation.org/wps/portal/surgeryskully Forearm fractures]
{{human anatomical features}}
{{Upper limb general}}
[[Category:Upper limb anatomy]]
[[ar:ساعد]]
[[de:Unterarm]]
[[es:Antebrazo]]
[[fa:ساعد]]
[[fr:Avant-bras]]
[[it:Avambraccio]]
[[he:אמה (איבר)]]
[[la:Antebrachium]]
[[lt:Dilbis]]
[[nl:Onderarm]]
[[pl:Przedramię]]
[[pt:Antebraço]]
[[ru:Предплечье]]
[[simple:Forearm]]
[[fi:Kyynärvarsi]]
[[sv:Underarm]]
[[te:ముంజేయి]]
[[th:ปลายแขน]]
[[tr:Önkol]]
[[uk:Передпліччя]]