Muscles of the Forearm and Hand

Forearm and Hand

 Muscle Origin Insertion Action Notes
Extensor digitorum Common extensor tendon from lateral epicondyle of humerus Dorsal surface of middle and distal phalanges 2-5
( four fingers)
Extends four fingers, assists in extension of the wrist
Pronator quadratus
Palmaris longus Medial epicondyle of humerus Palmar aponeurosis Flexion of hand and wrist Flex wrist against resistance to find tendon.May be absent in one or both sides in some people.
Flexor digitorum superficialis Medial epicondyle of humerus, coronoid process of ulna, proximal radius Four tendons into the middle phalanges of fingers 2-5, palmar surface Flexes the middle and proximal phalanges of fingers 2-5, flexion of the wrist and forearm. Median nerve and ulnar artery are under origin
Flexor carpi radialis Medial epicondyle of humerus Base of 2nd to base of 3rdmetacarpal bone Flexes and abducts the wrist, pronation of the forearm and flexion of the elbow
Flexor carpi ulnaris Medial epicondyle of humerus, medial olecranon and proximal posterior ulna Pisiform bone Flexes and adducts the wrist and flexes the elbow
Extensor carpi radialis longus Lateral supracondylar ridge of humerus Base of 2ndmetacarpal bone dorsal side Extends and abducts the wrist, flexes the elbow
Extensor carpi radialis brevis Lateral epicondyle of humerus Dorsal surface of base of 3rdmetacarpal bone Extends and assists in abduction of the wrist
Extensor carpi ulnaris Lateral epicondyle of humerus, posterior border of ulna Base of 5thmetacarpal bone, ulnar side Extends and adducts the wrist Tendon runs through a groove between the head of the ulna and the styloid process of ulna
Flexor digitorum profundus Anterior and medial surfaces of proximal ¾ of ulna Four tendons into bases of distal phalanges on anterior surface Flexes distal interphalangeal joints of four fingers, flexes proximal interphalageal and metacarpopphalangeal joints
Flexor pollicus longus Anterior surface of radius, deep to flexors Distal phalange of thumb Flexes thumb
Supinator Lateral epicondyle of humerus, posterior ulna Proximal anterior shaft of humerus Supinates forearm
Extensor pollicus longus and brevis Posterior surface of radius and ulna, deep to extensors Brevis –proximal phalange of thumbLongus- distal phalange of thumb Extends the thumb
Opponens pollicis Palmar retinaculum, trapezium 1st metacarpal anterior surface Opposition of thumb to each digit.Rotates 1st metacarpal so the thumbnail faces the ceiling when the hand is resting palm up.


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