Muscle Chart 2

Muscles that Act on the Elbow to Move the Forearm Muscle Action Origin Insertion Innervation Flexors (anterior arm)

Flexes elbow, powerful Long head: Supraglenoid tubercle of Radial tuberosity *Biceps brachii supinator of forearm scapula and bicipital Long head flexes GH joint Short head: Coracoid process of scapula aponeurosis Musculocutaneous nerve Brachialis Primary flexor of elbow Distal humerus Proximal ulna

Styloid process Brachioradialis Flexes elbow Lateral distal humerus Radial nerve of radius

Extensors (posterior arm)

Primary extensor of elbow Long head: Infraglenoid tubercle of scapula Olecranon *Triceps brachii Long head of triceps also Lateral head: Posterior humerus Radial nerve process of ulna extends GH Joint Medial head: Posterior humerus *Actions at both the elbow/forearm and glenohumeral joint are listed here.

Muscles of the Forearm Acting on the Forearm, Wrist, or Hand Muscle Action Origin Insertion Innervation Anterior Muscles: Superficial Pronator teres Pronates forearm Lateral radius Base of 2nd & 3rd Flexor carpi radialis Flexes wrist and abducts hand Median nerve metacarpals Medial epicondyle of humerus Palmaris longus Weak wrist flexor Palmar aponeurosis Medial carpal and Flexor carpi ulnaris Flexes wrist and adducts hand Ulnar nerve metacarpal bones Anterior Muscles: Intermediate Flexor digitorum Flexes wrist, 2nd–5th MP Middle phalanges Medial epicondyle of humerus Median nerve superficialis joints, and PIP joints of fingers 2–5 Anterior Muscles: Deep Flexes MP joint of thumb, IP Distal phalanx of Flexor pollicis longus Anterior shaft of radius Median nerve joint of thumb thumb Flexor digitorum Flexes wrist, 2nd–5th MP Distal phalanges of Lateral ½ = median nerve Anteromedial ulna profundus joints, PIP joints, & DIP joints fingers 2–5 Medial ½ = ulnar nerve Pronator quadratus Pronates forearm Distal ulna Distal radius Median Nerve Posterior Muscles: Superficial Extensor carpi Extends wrist, abducts hand Lateral distal humerus Base of 2nd metacarpal radialis longus Extensor carpi Extends wrist, abducts hand Base of metacarpal III radialis brevis Extends wrist, 2nd–5th MP Distal & middle Extensor digitorum Radial nerve joints, PIP joints, & DIP joints phalanges of digits 2–5 Lateral epicondyle of humerus Extensor digiti Extends wrist, MP, and PIP Proximal phalanx of minimi joints of finger 5 finger 5 Extensor carpi Extends wrist, adducts hand Base of 5th metacarpal ulnaris Posterior Muscles: Deep Abductor pollicis Lateral 1st Abducts thumb Proximal radius and ulna longus metacarpal Extensor pollicis Proximal phalanx of Extends MP joints of thumb Posterior radius brevis thumb Extensor pollicis Extends MP and IP joints of Distal phalanx of Posterior ulna Radial nerve longus thumb thumb Extends MP, PIP, and DIP Extensor digitorum Extensor indicis Posterior ulna joints of finger 2 tendon to 2nd finger Lateral epicondyle of humerus Supinator Supinates forearm Anterolateral radius & proximal ulna

Intrinsic Muscles of the Hand Muscle Action Innervation Thenar Group

Flexor pollicis brevis Flexes thumb

Abductor pollicis brevis Abducts thumb Median nerve

Opponens Pollicis Opposes thumb

Hypothenar Group

Flexor digiti minimi Flexes finger 5

Abductor digiti minimi Abducts finger 5 Ulnar nerve

Opponens digiti minimi Opposition of finger 5

Midpalmar Group Flexes 2nd–5th MP joints and extends Lateral 2 lumbricals: median nerve Lumbricals 2nd–5th PIP and DIP joints Medial 2 lumbricals: ulnar nerve Dorsal Interossei Abducts fingers 2–5

Palmar Interossei Adducts fingers 2–5 Ulnar nerve

Adductor Pollicis Adducts thumb