This MedLibrary.org supplementary page on Forearm is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
 |
This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (December 2007) |
| Forearm | |
|---|---|
 |
|
| Upper limb, forearm pronated. The forearm is the part of the upper limb between the elbow and the wrist. | |
| Latin | antebrachium |
| MeSH | Forearm |
| Dorlands/Elsevier | a_45/12138967 |
The forearm is the structure on the upper limb, between the elbow and the wrist.[1]. This term is used in anatomy to distinguish it from the arm (or upper arm). It is homologous to the leg that lies between the knee and the ankle joints.
Contents |
The human forearm
The forearm contains two long bones, the 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 compartments. 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 and 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, 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
Joints
- proximal to forearm
- in the forearm
- distal to forearm
| header 1 | header 2 | header 3 |
|---|---|---|
| row 1, cell 1 | row 1, cell 2 | row 1, cell 3 |
| row 2, cell 1 | row 2, cell 2 | row 2, cell 3 |
===Muscles===
- See also: Muscle table#Forearm
| 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 (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 (communis) | E | radial |
| Posterior | intermediate | 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 (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 and 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 (PT, FCR, PL, FDS).
- anterior interosseous nerve (supplies FPL, lat. 1/2 of FDP, PQ).
- Radial nerve - supplies muscles of the posterior compartment (ECRL, ECRB).
- Superficial branch of radial nerve
- Deep branch of radial nerve, becomes Posterior interosseus nerve and supplies muscles of the posterior compartment (ED, EDM, ECU, APL, EPB, EPL, EI).
- Ulnar nerve - supplies some medial muscles (FCU, med. 1/2 of FDP).
Vessels
Other structures
Additional images
 Superficial muscles of the forearm |
 Deep muscles of the forearm |
 Cross-section through the middle of the forearm. |
References
External links
|
|||||||||||||||||||
|
|||||||||||
Wikipedia content modification information:
- This page was last modified on 24 August 2008, at 16:07.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Forearm".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.