Transcript ch_10_lecture_outline_c

CHAPTER # 10(c)
THE MUSCULAR SYSTEM
(ANATOMY)
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Muscles Crossing the Shoulder Joint
• Nine muscles cross the shoulder joint to insert
on and move the humerus
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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
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Muscles Crossing the Shoulder Joint
PLAY
A&P Flix™: Pectoralis major
PLAY
A&P Flix™: Latissimus dorsi
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A&P Flix™: Deltoid
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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
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Muscles Crossing the Shoulder Joint
PLAY
A&P Flix™: Muscles that cross the glenohumeral joint
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A&P Flix™: Movement from the rotator cuff muscles (a)
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A&P Flix™: Movement from the rotator cuff muscles (b)
PLAY
A&P Flix™: Teres Major
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Rotator Cuff Anatomy and Function
PLAY
A&P Flix™: Subscapularis
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A&P Flix™: Supraspinatus
PLAY
A&P Flix™: Infraspinatus
PLAY
A&P Flix™: Teres minor
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A&P Flix™: Rotator cuff muscles
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Clavicle
Deltoid
Sternum
Pectoralis major
Coracobrachialis
Triceps brachii:
Lateral head
Long head
Medial head
Biceps brachii
Brachialis
Brachioradialis
(a) Anterior view
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Figure 10.14a
Rotator Cuff Anatomy and Function
PLAY
A&P Flix™: Scapular muscles of the glenohumeral joint (a)
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A&P Flix™: Axial muscles of the glenohumeral joint (a)
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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
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* Rotator cuff muscles
Figure 10.14b
Rotator Cuff Anatomy and Function
PLAY
A&P Flix™: Scapular muscles of the glenohumeral joint (b)
PLAY
A&P Flix™: Axial muscles of the glenohumeral joint (b)
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Table 10.12 Part 1
Movement at the Glenohumeral Joint
PLAY
A&P Flix™: Movement at the glenohumeral joint: An overview
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A&P Flix™: Movement at the glenohumeral joint (a)
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A&P Flix™: Movement at the glenohumeral joint (b)
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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)
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Clavicle
Deltoid
Sternum
Pectoralis major
Coracobrachialis
Triceps brachii:
Lateral head
Long head
Medial head
Biceps brachii
Brachialis
Brachioradialis
(a) Anterior view
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Figure 10.14a
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
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Muscles Crossing the Elbow Joint
• Posterior extensor muscles
• Triceps brachii—prime mover of forearm
extension
• Anconeus—weak synergist
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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
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* Rotator cuff muscles
Figure 10.14b
Muscles Crossing the Elbow Joint
PLAY
A&P Flix™: Muscles of the elbow joint (c)
PLAY
A&P Flix™: Triceps brachii
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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)
(a) Muscles of the arm
Anterior compartment
of arm (flexes elbow);
innervation:
musculocutaneous
nerve
PLAY
A&P Flix™: Movement at the elbow joint
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Figure 10.17a
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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
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Muscles of the Forearm
• Some forearm muscles act to produce
pronation and supination of the forearm
PLAY
A&P Flix™: Muscles of the forearm (a)
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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)
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A&P Flix™: Muscles of the forearm (c)
PLAY
A&P Flix™: Pronator teres
PLAY
A&P Flix™: Supinator
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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
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Superficial transverse
ligament of palm
Palmar aponeurosis
Flexor retinaculum
Flexor digitorum
superficialis
Flexor carpi ulnaris
Palmaris longus
Flexor carpi radialis
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Flexor pollicis longus
Extensor carpi radialis longus
Brachioradialis
Pronator teres
Medial epicondyle
of humerus
Medial head of
triceps brachii
Pronator quadratus
Tendon of biceps brachii
(a)
Biceps brachii
Figure 10.15a
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
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A&P Flix™: Flexor carpi ulnaris
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A&P Flix™: Flexor digitorum superificalis
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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)
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Figure 10.15c
Muscles of the Forearm: Anterior
Compartment
PLAY
A&P Flix™: Anterior Muscles of the wrist and fingers (a)
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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
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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)
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Figure 10.16a
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
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A&P Flix™: Extensor carpi radialis brevis
PLAY
A&P Flix™: Extensor digitorum
PLAY
A&P Flix™: Extensor carpi ulnaris(c)
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Interossei
Extensor indicis
Extensor pollicis brevis
Extensor pollicis longus
Abductor pollicis longus
Supinator
Anconeus
Olecranon process of ulna
(b)
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Figure 10.16b
Muscles of the Forearm: Posterior
Compartment
PLAY
A&P Flix™: Posterior Muscles of the wrist and fingers (a)
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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)
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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
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Anterior compartment
of forearm (flexes wrist
and fingers); innervation:
median or ulnar nerve
Figure 10.17b
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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 the thumb toward
the little finger
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Finger and Thumb Movements
• Flexion
• Thumb—bends medially along the palm
• Fingers—bend anteriorly
• Extension
• Thumb—points laterally
• Fingers—move posteriorly
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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
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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
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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 10.18a
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
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Abductor pollicis
brevis
Opponens pollicis
Flexor pollicis longus
tendon
Figure 10.18b
Palmar interossei
(c) Palmar interossei (isolated)
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Figure 10.18c
Dorsal interossei
(d) Dorsal interossei (isolated)
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Figure 10.18d
Intrinsic Muscles of the Hand
PLAY
Animation: Rotatable hand
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