Forearm Muscles: Anatomy and Function

Posted on Jan 12, 2025 in Geology

Anterior Group

Pronator Quadratus

It extends from the distal fourth of the ulna’s anterior face to the anteroexternal face of the distal fourth of the radius.

Function: Forearm pronation.

Flexor Digitorum Profundus

It originates from the proximal three-fourths of the ulna’s anterior face. It inserts via four tendons that pass through the wrist into the base of the third phalanx of the four ulnar digits.

Function: Flexion of the wrist, metacarpals, and third phalanges over the second ones.

Flexor Pollicis Longus

It originates from the medial part of the radius’s anterior face and inserts into the anterior face of the base of the thumb’s second phalanx.

Function: Flexion of the thumb’s second phalanx on the first one.

Flexor Digitorum Superficialis

It arises from the humeral epitrochlea, the coronoid process of the ulna, and the anterior face of the radius. It inserts via four tendons that pass through the wrist. In front of the first phalanx, the tendon divides into two bands that insert into the base of the second phalanx.

Pronator Teres

It arises from the epitrochlea and the coronoid process, and inserts into the anteroexternal face of the middle third of the superior radius.

Function: Forearm pronation.

Flexor Carpi Radialis

It arises from the humeral epitrochlea. It inserts via one tendon into the base of the second metacarpal.

Function: Main flexor of the wrist with a tendency to produce abduction.

Palmaris Longus

It originates from the humeral epitrochlea. It inserts into the superficial aponeurosis of the wrist and the carpal annular ligament.

Function: Wrist flexion.

Flexor Carpi Ulnaris

It is located on the internal border of the forearm. It arises from the epitrochlea, the olecranon’s posterior border, and the ulna, and inserts into the fifth metacarpal.

Function: Flexion of the wrist with adduction.

External Group

Supinator

It arises from the humeral epicondyle and the olecranon, and inserts into the anterior face of the superior third of the radius.

Function: Forearm supination.

Brachioradialis

It originates from the external border of the inferior third of the humerus and inserts into the styloid process of the radius.

Function: Forearm flexion and supination.

Extensor Carpi Radialis Longus

It is located below the brachioradialis and above the extensor carpi radialis brevis. It originates from the supracondylar area of the humerus and inserts into the posterior face of the base of the second metacarpal.

Function: To produce elbow flexion and wrist extension with abduction.

Extensor Carpi Radialis Brevis

It is located along the radius, below the extensor carpi radialis longus. It originates from the epicondyle and inserts into the posterior face of the base of the third metacarpal.

Function: To produce wrist extension.

Posterior Group

Abductor Pollicis Longus

It originates from the posterior ulnar side and inserts into the first metacarpal.

Function: Abduction of the thumb and hand. Extension of the hand.

Extensor Pollicis Brevis

It originates from the posterior face of the radius and ulna and inserts into the first phalanx of the thumb.

Function: Extension and abduction of the thumb.

Extensor Pollicis Longus

It originates from the posterior face of the middle third of the ulna and inserts into the posterior face of the base of the thumb’s second phalanx.

Function: Extension of the thumb.

Extensor Indicis

It originates from the posterior face of the inferior half of the ulna and inserts into the internal ulnar side of the common extensor tendon of the digits.