Forearm Muscles : Attachment, Nerve Supply & Action

Posted by Rafiqul Islam
May 14, 2018
Posted in Upper Limb

Forearm Muscles: The forearm is the region of the upper limb between the elbow and the wrist. The forearm muscles divided into-
Anterior compartment
Posterior compartment

 

 

Anterior Compartment

Anterior compartment of the forearm muscles divided into superficial & deep muscles.

Superficial muscles:
Pronator teres
palmaris longus
Flexor carpi radialis
Flexor carpi ulnaris
Flexor digitorum superficialis
Origin:
All superficial muscles are arises from the medial epicondyle of humerus but they are inserted into different part except

Pronator teres: It has two head.
Origin:
Humeral head: medial epicondyle of humerus
Ulnar head: Medial border of coronoid process of ulna
Insertion: Middle of the lateral aspect of the shaft of the radius.
Action: Pronation of forearm

Flexor carpi ulnaris:
Origin: It has two head.
Humeral head: medial epicondyle of humerus
Ulnar head: medial aspect of olecranon process of ulna and posterior border of ulna
Insertion: Pisiform bone, the hook of hamate and base of the 5th metacarpal bone
Action: Flexes and abducts hand at wrist joint

Palmaris longus:
Insertion: Flexor retinaculum and palmar aponeurosis
Action: Flexes wrist joint

Flexor carpi radialis:
Insertion: Bases of 2nd and 3rd metacarpal bones
Action: Flexes and abducts hand at wrist joint

Flexor carpi ulnaris:
Insertion: Pisiform bone, the hook of hamate and base of the 5th metacarpal bone
Action: Flexes and abducts hand at wrist jointforearm muscles

Flexor digitorum superficialis:
Insertion: The middle phalanx of 2nd to 5th digits ( four fingers)
Action: Flexes middle phalanx of fingers and assists in flexing proximal phalanx and wrist joint

Nerve supply:
All muscles are supplied by median nerve except flexor carpi ulnaris supplied by the ulnar nerve

Deep muscles:
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus

Flexor digitorum profundus( hybrid muscle):
Origin:
Upper three-fourths of the anterior and medial surface of the shaft of ulna
Upper three-fourths of the posterior border of ulna
Medial surface of the olecranon and coronoid processes of the ulna
Insertion: Flexor retinaculum( medial 4 digits)
Nerve supply:
Medial half by the ulnar nerve
Lateral half by anterior interosseous nerve(c8 , t1)
Action: Flexor of distal phalanges after the flexor digitorum superficialis has flexed the middle phalanges.

Flexor pollicis longus:
Origin: Upper three- fourths of the anterior surface of the shaft of the radius
Insertion: Palmar surface of the distal phalanx of the thumb
Nerve supply: Anterior interosseous nerve
Action: Flexes the distal phalanx of the thumbforearm deep anterior muscles

Pronator quadratus:
Origin: The oblique ridge on the lower one-fourth of the anterior surface of the shaft of ulna
Insertion: Lower one-fourth of the anterior surface and the anterior border of the radius, Ulnar notch
Nerve supply: Anterior interosseous nerve
Action: Pronate the forearm

You Might Also Like:

Carpal Tunnel: Symptom, Causes, Treatment & Exercise

Cubital Tunnel Syndrome: Causes, Symptoms, Diagnosis & Treatment

Dermatomes and Myotomes: Upper & Lower Limb

Posterior Compartment

Posterior compartment of the forearm muscles divided into superficial & deep muscles.
Superficial muscles:
Anconeus
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris

Superficial muscles:
Origin: All are arises from the lateral epicondyle of the humerus.
Anconeus:
Insertion: Lateral surface of olecranon process of ulna
Nerve supply: Radial nerve
Action: Extends elbow joint

Brachioradialis:
Insertion: The base of styloid process of radius
Nerve supply: Radial nerve
Action: Flexes forearm at the elbow joint and rotates forearm to the midprone position from supine or prone positions

Extensor carpi radialis longus:
Insertion: The posterior surface of the base of the 2nd metacarpal bone
Nerve supply: Radial nerve
Action: Extends and abducts hand at wrist jointposterior forearm muscles

Extensor carpi radialis brevis:
Insertion: The posterior surface of the base of the third metacarpal bone
Nerve supply: Deep branch of the radial nerve
Action: Extends and abducts hand at wrist joint

Extensor digitorum:
Insertion: Bases of middle phalanges of the 2nd-5th digits
Nerve supply: Deep branch of the radial nerve
Action: Extends fingers of the hand

Extensor digiti minimi:
Insertion: Extensor expansion of little finger
Nerve supply: Deep branch of the radial nerve
Action: Extends metacarpophalangeal joint of the little finger

Extensor carpi ulnaris:
Insertion: The base of the fifth metacarpal bone
Nerve supply: Deep branch of the radial nerve
Action: Extends and adducts hand at wrist joint

Deep muscles:
Supinator
Abductor pollicis longus
Abductor pollicis brevis
Extensor pollicis longus
Extensor indicis

Supinator:
Origin: Lateral epicondyle of humerus
Insertion: Neck and shaft of upper 1/3rd of radius
Nerve supply: Deep branch of the radial nerve
Action: Supination of the forearm when the elbow is extended

Abductor pollicis longus:
Origin: The posterior surface of the shaft of radius and ulna
Insertion: The base of the first metacarpal bone
Nerve supply: Deep branch of the radial nerve
Action: Abducts and extends the thumbDeep Posterior Compartment of forearm muscles

Extensor pollicis brevis:
Origin: The posterior surface of the shaft radius
Insertion: The base of proximal phalanx of the thumb
Nerve supply: Deep branch of the radial nerve
Action: Extends metacarpophalangeal joint of the thumb

Extensor pollicis brevis:
Origin: The posterior surface of the shaft of ulna
Insertion: The base of distal phalanx of the thumb
Nerve supply: Deep branch of the radial nerve
Action: Extends distal phalanx of the thumb

Forearm Movements

Supination of forearm muscles-Supinator.
Pronation of forearm muscles-Pronator teres & Pronator quadratus.
Elbow flexor muscles-Biceps brachii, Brachialis, Brachioradialis, Pronator teres.
Elbow extensor muscles-Triceps brachii & Anconeus