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Chapter 12, Part 1 Appendicular Muscles Arms Fig. 12.1 Superficial Deep Trapezius Deltoid (cut) Subclavius Subscapularis Deltoid Pectoralis minor Pectoralis major Teres major Serratus anterior Latissimus dorsi Long head Biceps brachii Short head Latissimus dorsi Long head Short head Biceps brachii Coracobrachialis • brachi = arm Anterior view Fig. 12.2 Superficial Deep Trapezius Levator scapulae Rhomboid minor Supraspinatus Deltoid Infraspinatus Teres minor Rhomboid major Teres minor Teres major Teres major Serratus anterior Latissimus dorsi Serratus posterior inferior External oblique Posterior view Deep Fig. 12.3 Protractors Pectoralis minor Serratus anterior Pectoralis minor Serratus anterior Retracted scapulae Protracted scapulae (“good posture”) (“poor posture”) (a) Retraction and protraction of scapula Anterior view Copyright © McGraw-Hill Education. Permission required for reproduction or display. Fig. 12.3 Superficial Deep Rhomboid minor Trapezius Retractors Trapezius Rhomboids Rhomboid major Retracted scapulae (“good posture”) (a) Retraction and protraction of scapula Posterior view Clavicle stabilizer • Subclavius strengthens and stabilizes clavicle Superficial Deep Subclavius Fig. 12.3 Superficial Elevators Rhomboid major Rhomboid minor Levator scapulae Trapezius (superior part) Trapezius Deep Levator scapulae Rhomboid minor Rhomboid major (b) Elevation and depression of scapula Fig. 12.3 Superficial Posterior Depressors Deep Anterior Trapezius (inferior part) Pectoralis minor Trapezius (b) Elevation and depression of scapula Pectoralis minor Fig. 12.3 Superior rotators Serratus anterior Trapezius (superior part) Superficial Posterior Deep Anterior Trapezius Serratus anterior (c) Superior and inferior rotation of scapula Fig. 12.3 Deep Posterior Inferior rotators of the scapula Levator scapulae Rhomboid major Rhomboid minor Levator scapulae • deep to trapezius and sternocleidomastoid • inserts on superior angle of scapula Rhomboid minor Rhomboid major (c) Superior and inferior rotation of scapula Fig. 12.4a Muscles that Move the Glenohumeral Joint Deltoid Pectoralis major Biceps brachii, long head Superficial Anterior Deltoid is prime abductor of arm • forms rounded contour of shoulder • anterior fibers flex and medially rotate arm • middle fibers adduct arm • posterior fibers extend and laterally rotate arm Fig. 12.4a Muscles that Move the Glenohumeral Joint Deltoid Pectoralis major Biceps brachii, long head Superficial Anterior Pectoralis major is principal flexor of arm • also adducts and medially rotates arm Fig. 12.4a Muscles that Move the Glenohumeral Joint Coracobrachialis is synergist to pectoralis major • flexes and adducts arm Deep Sternocleidomastoid Subclavius Subscapularis Coracobrachialis Pectoralis minor Serratus anterior Fig. 12.4b Muscles that Move the Glenohumeral Joint Deltoid Latissimus dorsi Superficial Trapezius Latissimus dorsi is principal arm extensor • inserts on intertubercular groove of humerus (anterior side) • also adducts and medially rotates arm Fig. 12.4b Muscles that Move the Glenohumeral Joint Teres major is synergist to latissimus dorsi • extends, adducts, and medially rotates arm • inserts on lesser tubercle and intertuburcular groove of humerus Deep Levator scapulae Supraspinatus Infraspinatus Teres minor Teres major Fig. 12.5 Rotator Cuff Clavicle Acromion Supraspinatus Coracoid process Subscapularis Humerus (a) Anterior view Provide strength and stability to glenohumeral joint; Attach scapula to humerus Subscapularis medially rotates and protracts arm Supraspinatus abducts the arm Fig. 12.5 Rotator Cuff Infraspinatus adducts and laterally rotates arm Teres minor adducts and laterally rotates arm Supraspinatus Infraspinatus Teres minor (b) Posterior view Fig. 12.5 Lateral Rotation Subscapularis Infraspinatus and teres minor Abduction Supraspinatus Medial Rotation Infraspinatus and teres minor Subscapularis (c) Movement of rotator cuff muscles (left): © Elsa/Getty Images; (middle): © Brita Meng Outzen/AP Photo; (right): © Mike Fiala/Getty Images Fig. 12.6 Anterior upper limb muscles are flexors. Anterior Biceps brachii View of cross section Brachialis Medial Lateral Humerus Triceps brachii Medial head Lateral head Long head Posterior Posterior upper limb muscles are extensors. Fig. 12.7 Deltoid Pectoralis major Coracobrachialis Biceps brachii, long head Brachioradialis Biceps brachii, short head Triceps brachii Brachialis Bicipital aponeurosis (a) Anterior view Biceps brachii is two-headed (and two-bellied) muscle • flexes and supinates forearm • originates on scapula; inserts on radial tuberosity Deep Anterior Fig. 12.7 Brachialis is deep to biceps brachii • most powerful flexor of forarm • originates on humerus; inserts on ulna Biceps brachii works when hand is supinated Brachialis works when hand is pronated Coracobrachialis Brachialis Coronoid process of ulna (b) Anterior muscles Fig. 12.8 Triceps brachii is 3-headed muscle • prime extensor of forearm • antagonistic to biceps brachii • originates on scapula and posterior humerus; inserts on olecranon of ulna Anconeus is weak elbow extensor, very short muscle Deep Posterior Supraspinatus Infraspinatus Teres minor Teres major Triceps brachii Anconeus Fig. 12.9 Medial epicondyle Lateral epicondyle Supinator Pronator teres Interosseous membrane Pronator quadratus Supination Medial epicondyle Lateral epicondyle Supinator Pronator teres Interosseous membrane Pronator quadratus Pronation Fig. 12.11 (a) Right anterior forearm, superficial view Brachioradialis is prominent muscle of forearm near elbow • synergist in forearm flexion; Brachioradialis used primarily when biceps and/or brachialis have already flexed elbow Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Flexor retinaculum Palmar aponeurosis Fig. 12.11 (a) Right anterior forearm, superficial view Anterior muscles of forearm are flexors • most originate on medial epicondyle of humerus • flex wrist, metacarpophalangeal (MP) joints, and/or interphalangeal (IP) joints Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Brachioradialis Palmaris longus Flexor carpi radialis Flexor retinaculum Palmar aponeurosis Fig. 12.11 (a) Right anterior forearm, superficial view Flexor retinaculum is fibrous band that holds tendons close to bones • Flexor tendons pass through Brachioradialis space between carpal bones and flexor retinaculum (the “carpal tunnel”), except palmaris longus Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Flexor retinaculum Palmar aponeurosis Page 368 Flexor pollicis longus tendon Carpal tunnel, anterior view Flexor digitorum superficialis tendon Palmaris longus tendon (cut) Median nerve Flexor digitorum profundus tendon Common flexor synovial sheath Flexor carpi radialis tendon Trapezium Flexor retinaculum covering carpal tunnel Common flexor synovial sheath Fig. 12.11 (a) Right anterior forearm, superficial view Muscle names explain function • Flexor carpi ulnaris flexes wrist and adducts hand Brachioradialis • Flexor carpi radialis flexes wrist and abducts hand • Palmaris longus is weak wrist flexor (not everyone has one) Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Flexor retinaculum Palmar aponeurosis Fig. 12.11 (b) Right anterior forearm, intermediate view Radius Ulna Intermediate layer of muscle • Flexor digitorum superficialis flexes wrist, MP and PIP joints (not DIP joints) in four fingers Flexor digitorum superficialis Flexor digitorum superficialis tendons Flexor digitorum profundus tendons Fig. 12.11 Deepest layer of muscle • Flexor pollicis longus flexes MP and IP joints of thumb; weakly flexes wrist • Flexor digitorum profundus flexes all joints of four fingers and wrist (c) Right anterior forearm, deep view Supinator Flexor pollicis longus Flexor digitorum profundus Pronator quadratus Flexor digitorum profundus tendons Fig. 12.14 Intrinsic Muscles of Hand • Lumbricals flex MP joints and extend POP and DIP joints of fingers 2-5 • Dorsal interossei are located between metacarpals; flex MP joints and extend POP and DIP joints of fingers 2-5 • Palmar interossei adduct fingers 2, 4, and 5; assists dorsal interossei and lumbricals Tendon sheath First dorsal interosseous Flexor digitorum profundus tendon Flexor digitorum superficialis tendon Lumbricals Flexor digiti minimi brevis Abductor digiti minimi Flexor retinaculum Flexor pollicis longus tendon Adductor pollicis Flexor pollicis brevis Abductor pollicis brevis Palmaris longus tendon (cut) (a) Right hand, superficial palmar view Page 368 Anterior View of cross section Palmaris longus tendon Flexor carpi radialis tendon Median nerve Flexor retinaculum covering carpal tunnel Ulnar artery Ulnar nerve Flexor digitorum superficialis tendons Carpal tunnel Flexor pollicis longus tendon Common flexor synovial sheath Flexor digitorum profundus tendons Trapezium Hamate Trapezoid Capitate Posterior Carpal tunnel, transverse section Fig. 12.13 Right posterior forearm, superficial view Extensor muscles are on posterior forearm • Extensor carpi radialis longus extends wrist and abducts hand at Anconeus wrist Flexor carpi ulnaris • Extensor carpi radialis brevis is Extensor carpi ulnaris synergist to extensor carpi radialis longus Extensor digiti minimi • Extensor digitorum extends wrist, MP, PIP and DIP joints of fingers 2-5 Extensor • Extensor digiti minimi extends retinaculum little finger Extensor digitorum • Extensor carpi ulnaris extends tendons wrist and adducts hand Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Abductor pollicis longus Extensor pollicis brevis Fig. 12.13 Extensor muscles are on posterior forearm • Extensor pollicis longus extends MP and IP joints of thumb • Extensor pollicis brevis extends MP joint of thumb • Abductor pollicis longus abducts thumb • Extensor indicis extends MP, PIP, and DIP joints of index finger Right posterior forearm, deep view Olecranon process of ulna Supinator Extensor pollicis longus Extensor indicis Dorsal interossei Abductor pollicis longu Extensor pollicis brevis
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