Power Point Lecture Slides prepared by Janice Meeking

Muscles Crossing the Shoulder Joint • Nine muscles cross the shoulder joint to insert

Muscles Crossing the Shoulder Joint • Some originate off the scapula; others originate off the axial skeleton • Three are prime movers of the arm • Pectoralis major • Latissimus dorsi • Deltoid • Actions include flexion, extension, adduction, abduction, and rotation of humerus Copyright © 2010 Pearson Education, Inc.

Muscles Crossing the Shoulder Joint PLAY A&P Flix™: Pectoralis major PLAY A&P Flix™: Latissimus

Muscles Crossing the Shoulder Joint • Four muscles are rotator cuff muscles • Supraspinatus • Infraspinatus • Teres minor • Subscapularis • Reinforce the capsule of the shoulder • Act as synergists and fixators • Two additional muscles are synergists: coracobrachialis and teres major Copyright © 2010 Pearson Education, Inc.

Muscles Crossing the Shoulder Joint PLAY A&P Flix™: Muscles that cross the glenohumeral joint PLAY A&P Flix™: Movement from the rotator cuff muscles (a) PLAY A&P Flix™: Movement from the rotator cuff muscles (b) PLAY A&P Flix™: Teres Major Copyright © 2010 Pearson Education, Inc.

Rotator Cuff Anatomy and Function PLAY A&P Flix™: Subscapularis PLAY A&P Flix™: Supraspinatus PLAY A&P Flix™: Infraspinatus PLAY A&P Flix™: Teres minor PLAY A&P Flix™: Rotator cuff muscles Copyright © 2010 Pearson Education, Inc.

Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Copyright © 2010 Pearson Education, Inc. Figure 10. 14 a

Rotator Cuff Anatomy and Function PLAY A&P Flix™: Scapular muscles of the glenohumeral joint

Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view Copyright © 2010 Pearson Education, Inc. * Rotator cuff muscles Figure 10. 14 b

Copyright © 2010 Pearson Education, Inc. Table 10. 12 Part 1

Movement at the Glenohumeral Joint PLAY A&P Flix™: Movement at the glenohumeral joint: An overview PLAY A&P Flix™: Movement at the glenohumeral joint (a) PLAY A&P Flix™: Movement at the glenohumeral joint (b) Copyright © 2010 Pearson Education, Inc.

Muscles Crossing the Elbow Joint • Anterior flexor muscles • Brachialis and biceps brachii—chief forearm flexors • Brachioradialis—synergist and stabilizer PLAY A&P Flix™: The elbow joint and forearm: An overview PLAY A&P Flix™: Muscles of the elbow joint (a) Copyright © 2010 Pearson Education, Inc.

Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Copyright © 2010 Pearson Education, Inc. Figure 10. 14 a

Muscles Crossing the Elbow Joint PLAY A&P Flix™: Muscles of the elbow joint (b) PLAY A&P Flix™: Biceps brachii PLAY A&P Flix™: Brachialis PLAY A&P Flix™: Brachioradialis Copyright © 2010 Pearson Education, Inc.

Muscles Crossing the Elbow Joint • Posterior extensor muscles • Triceps brachii—prime mover of

Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view Copyright © 2010 Pearson Education, Inc. * Rotator cuff muscles Figure 10. 14 b

Muscles Crossing the Elbow Joint PLAY A&P Flix™: Muscles of the elbow joint (c)

Triceps brachii Lateral head Long head Medial head Humerus Extensors Flexors Brachialis Others Posterior compartment of arm (extends elbow); innervation: radial nerve Short head Biceps brachii Long head (a) Muscles of the arm Anterior compartment of arm (flexes elbow); innervation: musculocutaneous nerve PLAY A&P Flix™: Movement at the elbow joint Copyright © 2010 Pearson Education, Inc. Figure 10. 17 a

Copyright © 2010 Pearson Education, Inc. Table 10. 12 Part 2

Muscles of the Forearm • Actions: movements of the wrist, hand, and fingers • Most anterior muscles are flexors and insert via the flexor retinaculum • Most posterior muscles are extensors and insert via the extensor retinaculum PLAY A&P Flix™: Muscles that act on the wrist and fingers: An overview Copyright © 2010 Pearson Education, Inc.

Muscles of the Forearm • Some forearm muscles act to produce pronation and supination

Muscles of the Forearm • Pronators: pronator teres and pronator quadratus • Supinator: a synergist with the biceps brachii PLAY A&P Flix™: Muscles of the forearm (b) PLAY A&P Flix™: Muscles of the forearm (c) PLAY A&P Flix™: Pronator teres PLAY A&P Flix™: Supinator Copyright © 2010 Pearson Education, Inc.

Muscles of the Forearm: Anterior Compartment • Flexors • Flexor carpi radialis • Palmaris longus • Flexor carpi ulnaris • Flexor digitorum muscles (superficialis and profundus) • Flexor pollicis longus PLAY A&P Flix™: Carpal tunnel Copyright © 2010 Pearson Education, Inc.

Superficial transverse ligament of palm Palmar aponeurosis Flexor retinaculum Flexor digitorum superficialis Flexor carpi ulnaris Pronator quadratus Flexor pollicis longus Palmaris longus Flexor carpi radialis Extensor carpi radialis longus Medial epicondyle of humerus Pronator teres Medial head of triceps brachii Copyright © 2010 Pearson Education, Inc. Brachioradialis Tendon of biceps brachii (a) Biceps brachii Figure 10. 15 a

Muscles of the Forearm: Anterior Compartment PLAY A&P Flix™: Anterior Muscles of the wrist and fingers (b) PLAY A&P Flix™: Flexor carpi radialis PLAY A&P Flix™: Flexor carpi ulnaris PLAY A&P Flix™: Flexor digitorum superficialis Copyright © 2010 Pearson Education, Inc.

Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis (cut) Lumbricals Tendon of flexor pollicis longus Thenar muscles of thumb Tendon of flexor carpi ulnaris (cut) Pronator quadratus Flexor pollicis longus Flexor digitorum profundus Supinator (c) Copyright © 2010 Pearson Education, Inc. Figure 10. 15 c

Muscles of the Forearm: Posterior Compartment • Extensors • Extensor carpi radialis longus and brevis • Extensor digitorum • Extensor carpi ulnaris • Extensor pollicis brevis and longus • Extensor indicis • Abductor pollicis longus Copyright © 2010 Pearson Education, Inc.

Extensor expansion Tendons of extensor digitorum Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus Extensor digitorum Extensor carpi radialis brevis Extensor carpi radialis longus Tendons of extensor carpi radialis brevis and longus Extensor indicis Extensor digiti minimi Extensor carpi ulnaris Flexor carpi ulnaris Anconeus Insertion of triceps brachii Brachioradialis (a) Copyright © 2010 Pearson Education, Inc. Figure 10. 16 a

Muscles of the Forearm: Posterior Compartment PLAY A&P Flix™: Posterior Muscles of the wrist and fingers (b) PLAY A&P Flix™: Extensor carpi radialis longus PLAY A&P Flix™: Extensor carpi radialis brevis PLAY A&P Flix™: Extensor digitorum PLAY A&P Flix™: Extensor carpi ulnaris(c) Copyright © 2010 Pearson Education, Inc.

Interossei Extensor indicis Extensor pollicis brevis Extensor pollicis longus Abductor pollicis longus Supinator Anconeus Olecranon process of ulna (b) Copyright © 2010 Pearson Education, Inc. Figure 10. 16 b

Movements of the Wrist and Fingers • Flexion and extension PLAY A&P Flix™: Movements of the wrist and fingers (a) • Abduction and adduction PLAY A&P Flix™: Movements of the wrist and fingers (b) Copyright © 2010 Pearson Education, Inc.

Posterior compartment of forearm (extends wrist and fingers); innervation: radial nerve Extensors Others Radius Abductor pollicis longus Pronator teres Brachioradialis (elbow flexor) Ulna Flexors (b) Muscles of the forearm (b) Extensors Flexors Others Copyright © 2010 Pearson Education, Inc. Anterior compartment of forearm (flexes wrist and fingers); innervation: median or ulnar nerve Figure 10. 17 b

Copyright © 2010 Pearson Education, Inc. Figure 10. 12 Part 3

Intrinsic Muscles of the Hand • Small weak muscles • Lie entirely within the palm of the hand • Control precise movements of metacarpals and fingers (e. g. , threading a needle) • Abductors and adductors of the fingers • Produce opposition—move thumb toward the little finger Copyright © 2010 Pearson Education, Inc.

Finger and Thumb Movements • Flexion • Thumb—bends medially along the palm • Fingers—bend anteriorly • Extension • Thumb—points laterally • Fingers—move posteriorly Copyright © 2010 Pearson Education, Inc.

Intrinsic Muscles of the Hand • Three groups • Thenar eminence (ball of the thumb) • Hypothenar eminence (ball of the little finger) • Each of the above groups has a flexor, an abductor, and an opponens muscle • Midpalmar muscles: lumbricals and palmar and dorsal interossei extend the fingers • Interossei muscles also abduct and adduct the fingers Copyright © 2010 Pearson Education, Inc.

Tendons of: Flexor digitorum profundus Flexor digitorum superficialis Third lumbrical Fourth lumbrical Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi Pisiform bone Flexor carpi ulnaris tendon Flexor digitorum superficialis tendons (a) First superficial layer Copyright © 2010 Pearson Education, Inc. Fibrous sheath Second lumbrical Dorsal interossei First lumbrical Adductor pollicis Flexor pollicis brevis Abductor pollicis brevis Opponens pollicis Flexor retinaculum Abductor pollicis longus Tendons of: Palmaris longus Flexor carpi radialis Flexor pollicis longus Figure 10. 18 a

Flexor digitorum profundus tendon Flexor digitorum superficialis tendon Dorsal interossei Palmar interossei Adductor pollicis Opponens digiti minimi Flexor pollicis brevis Flexor digiti minimi brevis (cut) Abductor digiti minimi (cut) (b) Second layer Copyright © 2010 Pearson Education, Inc. Abductor pollicis brevis Opponens pollicis Flexor pollicis longus tendon Figure 10. 18 b