Forearm . The forearm is one of the four parts into which the upper or thoracic limb is divided, the third being of them. The forearm is limited by its upper face with the arm through the elbow and by its lower face with the hand through the wrist joint .
Summary
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- 1 Description
- 2 bones
- 3 Forearm fractures
- 4 muscles
- 5 Anterior region of the forearm
- 6 Posteroexternal region of the forearm
- 7 Posterior region of the forearm
- 8 Sources
Description
The forearm is one of the four parts into which the upper or thoracic limb is divided, the third being of them. The forearm is limited by its upper face with the arm through the elbow and by its lower face with the hand through the wrist joint.
Bones
The skeleton of the forearm is made up of two long bones: the radius (external bone) and the ulna (internal bone).
The radius articulates with the arm bone, the humerus, with the ulna itself (ulna), and with the scaphoid and lunate carpal bones. The ulna (formerly called Nachi) articulates only with the arm bone, the humerus, and the radius.
It is formed by the radicubital (radioulnar) joint that consists of the union, by the superior and inferior zone, of the ulna and radius. Between them there is a space covered by very resistant fibro-cartilage (synchondrosis). This joint is the one that allows pronation and supination movements, where the radius rotates around the ulna.
Forearm fractures
The forearm region is one of the most frequently injured, the wrist being the place where most of the total fractures of a human being occur, regardless of their age group.
- Monteggia fracture
- Galeazzi fracture
- Essex-Lopresti fracture
- Colles fracture
Muscles
The muscular region of the forearm is made up of twenty muscles, and they are divided into three muscular regions:
- anterior region,
- postero-external region,
- posterior region.
Anterior region of the forearm
It contains four muscle planes with eight muscles, which are, from the most superficial to the deepest:
Foreground:
Lateromedially, we find:
- round pronator,
- palmar major, or carpal radial flexor
- palmar minor, or palmaris longus
- anterior ulnar, or flexor carpi ulnaris
Background:
The flexor digitorum superficialis is found, which contains four fascicles.
Third plane:
- deep flexor of the fingers, consisting of four fascicles ;
- long flexor of the thumb.
Fourth plane:
square pronator.
Posteroexternal region of the forearm
It contains four muscles that are, from the most superficial to the deepest:
- long supinator, or brachioradial
- carpal long radial extensor,
- carpal short radial extensor,
- short supinator, or supinator.
Posterior region of the forearm
It contains two muscle planes with a total of eight muscles.
Superficial plane Contains four muscles. Described in a lateromedial sense, we find:
Anconeus (found only in 3 people out of 10) common extensor digitorum, divided into three fascicles; own extensor of the little finger ; posterior ulnar.
Deep Plane Contains five muscles. Described in lateromedial and anteroposterior sense we find:
- Short extensor of the Thumb,
- Long thumb abductor,
- Long extensor of the Thumb,
- own extender of the Index.
In the upper part of the forearm is the small anconeus muscle .
