Lecture Human anatomy and physiology - Chapter 10: The muscular system (part c)

atus*
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

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A&P Flix™: Muscles of the elbow joint (c)

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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

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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
Pronator quadratus
Flexor digitorum
superficialis
Flexor carpi ulnaris
Palmaris longus
Flexor carpi radialis

Flexor pollicis longus
Extensor carpi radialis longus
Brachioradialis
Pronator teres

Medial epicondyle
of humerus

Tendon of biceps brachii

Medial head of
triceps brachii

Biceps brachii
(a)

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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

PLAY

A&P Flix™: Flexor carpi ulnaris

PLAY

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

PLAY

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 pollicis
brevis

Abductor digiti minimi
(cut)

Opponens pollicis

(b) Second layer
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Flexor pollicis longus
tendon
Figure 10.18b