Forearm

Forearm
Upper limb, forearm pronated. The forearm is the part of the upper limb between the elbow and the wrist.
Latin antebrachium
MeSH Forearm

The forearm is the structure and distal region of the upper limb, between the elbow and the wrist.[1] The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb but in anatomy, technically means only the region of the upper arm whereas the lower "arm" is called the forearm. It is homologous to the leg that lies between the knee and the ankle joints.

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.

Contents

Anatomy

Bones

Joints

Muscles

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

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)

Vessels

Other structures

Fracture

A fracture of the forearm can be classified as to whether it involves only the ulna (ulnar fracture), only the radius (radius fracture) or both (radioulnar fracture)

Additional images

Superficial muscles of the forearm  
Deep muscles of the anterior forearm  
Deep muscles of the posterior forearm  
Cross-section through the middle of the forearm.  

References

  1. ^ Forearm at eMedicine Dictionary

See also