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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Human Anatomy & Physiology SEVENTH EDITION
Elaine N. Marieb Katja Hoehn
PowerPoint® Lecture Slides prepared by Vince Austin, Bluegrass Technical and Community College
C H
A P
T E
R
10 The Muscular System
P A R T C
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
H. Extrinsic Shoulder Muscles
1. Muscles of the thorax
2. Anterior a. Pectoralis major (inserts into humerus; all others insert into pectoral girdle)
b. Pectoralis minor c. Serratus anterior d. Subclavius
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3. Posterior a. Latissimus Dorsi b. Trapezius Muscles c. Levator Scapulae d. Rhomboids
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4. These muscles are involved with the movements of the scapula including
a. Elevation
b. Depression
c. Rotation
d. Lateral and medial movements
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5. Prime movers of shoulder elevation are
a. Trapezius
b. Levator scapulae
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I. Muscles Crossing the Shoulder 1. Nine muscles cross the
shoulder joint and insert into the humerus
2. Prime movers include:
a. Pectoralis major
1) arm flexion
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
I. Muscles Crossing the Shoulder b. Latissimus dorsi and
posterior fibers of the deltoid 1) arm extension
c. Middle fibers of the deltoid 1) arm abduction
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
3. Rotator cuff muscles originate on the scapula a. Supraspinatus b. Infraspinatus c. teres minor d. subscapularis
4. Function mainly to reinforce the capsule of the shoulder
5. Secondarily act as synergists and fixators
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
6. The coracobrachialis and teres major:
a. Act as synergists
b. Do not contribute to reinforcement of the shoulder joint
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1. Forearm extension a. Triceps brachii is the prime
mover of forearm extension b. The anconeus is a weak synergist
A. Muscles Crossing the Elbow
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A. Muscles Crossing the Elbow 2. Forearm flexion
a. Brachialis and biceps brachii are the chief forearm flexors
b. Brachioradialis acts as a synergist and helps stabilize the elbow
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B. Muscles of the Forearm
1. Forearm muscle groups
a. those that move the wrist
b. those that move the digits
2. Anterior muscles are flexors
3. Posterior muscles are extensors
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
4. The pronator teres and pronator quadratus are not flexors, but pronate the forearm
5. The supinator muscle is a synergist with the biceps brachii in supinating the forearm
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C. Muscles of the Forearm: Anterior Compartment 1. These muscles
are primarily flexors of the wrist and fingers
Figure 10.15a
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D. Muscles of the Forearm: Posterior Compartment 1. These muscles are
primarily extensors of the wrist and fingers
Figure 10.16a Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
E. Intrinsic Muscles of the Hand 1. These small muscles:
a. Lie in the palm of the hand (none on the dorsal side)
b. Move the metacarpals and fingers
c. Control precise movements (e.g., threading a needle)
d. Are the main abductors and adductors of the fingers
e. Produce opposition – move the thumb toward the little finger
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Intrinsic Muscles of the Hand
Figure 10.18a Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Intrinsic Muscles of the Hand
Figure 10.18b
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
F. Finger and Thumb Movements
1. Flexion
a. Thumb – bends medially along the palm
b. Fingers – bend anteriorly
2. Extension
a. Thumb – points laterally
b. Fingers – move posteriorly
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G. Intrinsic Muscles of the Hand: Groups
1. There are two groups of intrinsic hand muscles
a. The thenar eminence (ball of the thumb)
b. hypothenar eminence (ball of the little finger)
c. each have a flexor, an abductor, and an opponens muscle
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2. The midpalm muscles
a. Lumbricals
b. Interossei
c. extend the fingers
3. The interossei also abduct and adduct the fingers