Chapter 12, Part 1 Appendicular Muscles Arms

Fig DeepSuperficial Trapezius Deltoid Pectoralis major Latissimus dorsi Anterior view Coracobrachialis Long head Short head Latissimus dorsi Serratus anterior Teres major Deltoid (cut) Subclavius Subscapularis Pectoralis minor Biceps brachii Short head Long head Biceps brachii brachi = arm

Fig Trapezius Deltoid Teres minor Teres major Latissimus dorsi Posterior view External oblique Serratus posterior inferior Serratus anterior Teres major Rhomboid minor Supraspinatus Levator scapulae Infraspinatus Rhomboid major Teres minor SuperficialDeep

Fig Protractors Pectoralis minor Serratus anterior Retracted scapulae (“good posture”) Protracted scapulae (“poor posture”) (a) Retraction and protraction of scapula Copyright © McGraw-Hill Education. Permission required for reproduction or display. Serratus anterior Pectoralis minor Deep Anterior view

Fig Retractors Trapezius Rhomboids Retracted scapulae (“good posture”) (a) Retraction and protraction of scapula Trapezius Posterior view Rhomboid minor Rhomboid major SuperficialDeep

Clavicle stabilizer Subclavius strengthens and stabilizes clavicle SuperficialDeep Subclavius

Fig Elevators Rhomboid major Rhomboid minor Levator scapulae Trapezius (superior part) (b) Elevation and depression of scapula SuperficialDeep Trapezius Rhomboid minor Rhomboid major Levator scapulae

Fig Depressors Trapezius (inferior part) Pectoralis minor (b) Elevation and depression of scapula Superficial Posterior Trapezius Pectoralis minor Deep Anterior

Fig (c) Superior and inferior rotation of scapula Serratus anterior Deep Anterior Superficial Posterior Trapezius Superior rotators Serratus anterior Trapezius (superior part)

Fig (c) Superior and inferior rotation of scapula Inferior rotators of the scapula Rhomboid major Rhomboid minor Levator scapulae deep to trapezius and sternocleidomastoid inserts on superior angle of scapula Deep Posterior Rhomboid minor Rhomboid major Levator scapulae

Deltoid Pectoralis major Biceps brachii, long head Superficial Anterior Fig. 12.4a Muscles that Move the Glenohumeral Joint 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

Deltoid Pectoralis major Biceps brachii, long head Superficial Anterior Fig. 12.4a Muscles that Move the Glenohumeral Joint Pectoralis major is principal flexor of arm also adducts and medially rotates arm

Serratus anterior Pectoralis minor Deep Sternocleidomastoid Subclavius Coracobrachialis Subscapularis Fig. 12.4a Muscles that Move the Glenohumeral Joint Coracobrachialis is synergist to pectoralis major flexes and adducts arm

Fig. 12.4b Muscles that Move the Glenohumeral Joint Superficial Trapezius Deltoid Latissimus dorsi 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 Deep Levator scapulae Supraspinatus Infraspinatus Teres minor Teres major Teres major is synergist to latissimus dorsi extends, adducts, and medially rotates arm inserts on lesser tubercle and intertuburcular groove of humerus

Fig 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 Rotator Cuff (b) Posterior view Supraspinatus Infraspinatus Teres minor Infraspinatus adducts and laterally rotates arm Teres minor adducts and laterally rotates arm

Fig (left): © Elsa/Getty Images; (middle): © Brita Meng Outzen/AP Photo; (right): © Mike Fiala/Getty Images Subscapularis Infraspinatus and teres minor Subscapularis Supraspinatus (c) Movement of rotator cuff muscles Lateral RotationMedial RotationAbduction

Fig Anterior Biceps brachii Brachialis Medial Anterior upper limb muscles are flexors. Posterior Triceps brachii Posterior upper limb muscles are extensors. Medial head Lateral head Long head Humerus Lateral View of cross section

Fig Deltoid Pectoralis major Coracobrachialis Biceps brachii, long head Biceps brachii, short head Triceps brachii Brachialis Brachioradialis 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

Fig Deep Anterior Coracobrachialis Brachialis Coronoid process of ulna (b) Anterior muscles 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

Fig Supraspinatus Infraspinatus Teres minor Teres major Triceps brachii Anconeus 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

Fig 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 (a) Right anterior forearm, superficial view Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Brachioradialis Flexor retinaculum Palmar aponeurosis Brachioradialis is prominent muscle of forearm near elbow synergist in forearm flexion; used primarily when biceps and/or brachialis have already flexed elbow

Fig (a) Right anterior forearm, superficial view Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Brachioradialis Flexor retinaculum Palmar aponeurosis Anterior muscles of forearm are flexors most originate on medial epicondyle of humerus flex wrist, metacarpophalangeal (MP) joints, and/or interphalangeal (IP) joints

Fig (a) Right anterior forearm, superficial view Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Brachioradialis Flexor retinaculum Palmar aponeurosis Flexor retinaculum is fibrous band that holds tendons close to bones Flexor tendons pass through space between carpal bones and flexor retinaculum (the “carpal tunnel”), except palmaris longus

Page 368 Palmaris longus tendon (cut) Median nerve Flexor carpi radialis tendon Trapezium Flexor digitorum superficialis tendon Flexor digitorum profundus tendon Common flexor synovial sheath Flexor retinaculum covering carpal tunnel Common flexor synovial sheath Carpal tunnel, anterior view Flexor pollicis longus tendon

Fig (a) Right anterior forearm, superficial view Medial epicondyle Common flexor tendon Pronator teres Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Brachioradialis Flexor retinaculum Palmar aponeurosis Muscle names explain function Flexor carpi ulnaris flexes wrist and adducts hand Flexor carpi radialis flexes wrist and abducts hand Palmaris longus is weak wrist flexor (not everyone has one)

Fig Radius Ulna Flexor digitorum superficialis Flexor digitorum superficialis tendons Flexor digitorum profundus tendons (b) Right anterior forearm, intermediate view Intermediate layer of muscle Flexor digitorum superficialis flexes wrist, MP and PIP joints (not DIP joints) in four fingers

Fig Supinator Flexor pollicis longus Flexor digitorum profundus Pronator quadratus Flexor digitorum profundus tendons (c) Right anterior forearm, deep view 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

Fig Tendon sheath Flexor digitorum profundus tendon Flexor digitorum superficialis tendon First dorsal interosseous 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 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

Page 368 Anterior Palmaris longus tendon Median nerve Flexor retinaculum covering carpal tunnel Ulnar artery Ulnar nerve Flexor digitorum superficialis tendons Carpal tunnel Flexor digitorum profundus tendons Trapezium Trapezoid Hamate Capitate Posterior Carpal tunnel, transverse section Flexor pollicis longus tendon Common flexor synovial sheath Flexor carpi radialis tendon View of cross section

Fig Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Abductor pollicis longus Extensor pollicis brevis Anconeus Flexor carpi ulnaris Extensor carpi ulnaris Extensor digiti minimi Extensor retinaculum Extensor digitorum tendons Extensor muscles are on posterior forearm Extensor carpi radialis longus extends wrist and abducts hand at wrist Extensor carpi radialis brevis is synergist to extensor carpi radialis longus Extensor digitorum extends wrist, MP, PIP and DIP joints of fingers 2-5 Extensor digiti minimi extends little finger Extensor carpi ulnaris extends wrist and adducts hand Right posterior forearm, superficial view

Fig Supinator Abductor pollicis longus Extensor pollicis brevis (b) Right posterior forearm, deep view Olecranon process of ulna Extensor pollicis longus Extensor indicis Dorsal interossei 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