Muscles of the Anterior Arm and Forearm

Muscles of the Anterior Arm and Forearm (Most Superfical) Deltoid Biceps brachii Triceps brachii Brachialis Pronator teres Flexor carpi radialis Brachioradialis Palmaris longus Extensor carpi radialis longus (posterior - just visible here) Flexor pollicis longus Pronator quadratus Thenar muscles of the thumb Flexor carpi ulnaris Flexor digitorum superficialis (deep to the above 3 muscles) Flexor retinaculum Palmar aponeurosis (fascia) Muscles of the Anterior Arm and Forearm (Most Superfical) Deltoid Biceps brachii Triceps brachii Brachialis Pronator teres Flexor carpi radialis Brachioradialis Palmaris longus Extensor carpi radialis longus (posterior - just visible here) Flexor pollicis longus Pronator quadratus Thenar muscles of the thumb Flexor carpi ulnaris Flexor digitorum superficialis (deep to the above 3 muscles) Flexor retinaculum Palmar aponeurosis (fascia) Muscles of the Anterior Arm and Forearm (Most Superfical) Muscles that Cross the Elbow (Moving the Forearm) (Anterior) 1) Deltoid (Visible, but not part of this group as it moves arm from the shoulder) 2) Biceps brachii a. Actions: flexes and supinates forearm (supinate rotates forearm laterally) – these act together for pulling tissue from tissue box, also a minor arm flexor b. Innervation: Musculocutaneous nerve c. Origin: from coracoid process and supraglenoid tubercle on scapula d. Insertion: through intertubercular groove of humerus to insert on radial tuberosity 1 2 3 2 3) Triceps brachii (Visible, but posterior) 4) Brachialis a. Actions: flexes forearm b. Innervation: Musculocutaneous nerve c. Origin: from anterior distal humerus d. Insertion: to coronoid process of the ulna 5) Brachioradialis a. Actions: flexes forearm (though doesn’t initiate flexion) b. Innervation: Radial nerve c. Origin: from distal humerus d. Insertion: to styloid process of the radius 3 4 5 (deep) (deep) 13 7 8 9 12 (deep) 6 14 15 10 11 (deeper) Muscles of the Anterior Arm and Forearm (Superficial Muscles) Muscles of the Forearm (Moving Wrist, Hand and Fingers) (Anterior Compartment – Flexors) l. Superficial Muscles 6) Pronator teres a. Actions: pronates (medial rotates) forearm, weak flexor of the forearm b. Innervation: Median nerve c. Origin: from medial epicondyle of the humerus and coronoid process of ulna d. Insertion: to the lateral shaft of the radius 7) Flexor carpi radialis a. Actions: flexes wrist, abducts hand, week flexor at elbow b. Innervation: Median nerve c. Origin: from medial epicondyle of the humerus d. Insertion: to the base of 2nd and 3rd metacarpals (wrist pulse area) 1 2 3 2 3 8) Palmaris longus a. Actions: weak wrist flexor b. Innervation: Median Nerve 4 c. Origin: from medial epicondyle of the humerus d. Insertion: to the palmar aponeurosis 9) Flexor carpi ulnaris a. Actions: flexes wrist, adducts hand b. Innervation: Ulnar nerve c. Origin: from medial epicondyle of humerus and olecranon process of ulna d. Insertion: to the base of the 5th metacarpal and pisiform bone (carpal). 10) Flexor digitorum superficialis a. Actions: flexes wrist, flexes middle phalanges of fingers 2-5 (important finger flexor for fast flexion against resistance) b. Innervation: Medial nerve c. Origin: from medial epicondyle of the humerus, coronoid process of ulna, and shaft or radius d. Insertion: to the four tendons into the middle phalanges of fingers 2-5. 5 7 8 9 12 (deep) (deep) 13 (deep) 6 14 15 10 11 (deeper) Muscles of the Anterior Arm and Forearm (Deep Muscles) Muscles of the Forearm (Moving Wrist, Hand and Fingers) (Anterior Compartment – Flexors) Continued... 1 ll. Deep Muscles 11) Flexor pollicus longus a. Actions: flexes distal phalanx of thumb, weak wrist flexor b. Innervation: Median nerve c. Origin: from anterior radius d. Insertion: to distal phalanx of thumb 2 2 12) Flexor digitorum profundus a. Actions: flexes fingers, weak wrist flexor, flexes distal interphalangeal joint b. Innervation: Median nerve does lateral half, Ulnar nerve does medial half of muscle c. Origin: from anterior medial surface of ulna d. Insertion: into four tendons of distal phalanges of fingers 2-5 13) Pronator Quadratus a. Actions: pronates forearm (with pronator teres), holds radius and ulna together b. Innervation: Median nerve c. Origin: from anterior distal ulna d. Insertion: to distal anterior radius Not muscles: 14) Flexor retinaculum: (also called the transverse carpal ligament and forms the carpal tunnel) 15) Palmar aponeurosis: (fascia that lies over the tendons of hand) 3 4 5 6 7 8 9 12 (deep) (deep) 13 (deep) 3 14 15 10 11 (deeper) Pronator quadtratus Flexor pollicis longus Extensor carpi radialis longus (just visible here) Brachioradialis Pronator teres 1. Most Superfical Muscles of Anterior Forearm Flexor digitorum superficialis (deep to the above three muscles) Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Extensor carpi radialis longus 2. Beneath Superfical Pronator quadratus Flexor pollicus longus Flexor digitorum superficialis Flexor digitorum profundus Supinator Ulna Radius Humerus 3. Deep Muscles of the Anterior Arm and Forearm (Deep Muscles) Humerus Ulna Radius Supinator Extensor carpi radialis longus Flexor digitorum superficialis Flexor pollicus longus Pronator quadratus Muscles of the Anterior Arm and Forearm (Deepest Muscles) Humerus Ulna Radius Supinator Flexor digitorum profundus Flexor pollicus longus Pronator quadratus