Download - Copyright © 2010 Pearson Education, Inc. Muscles of the Body Part C Adapted for H. Biology II 2014-2015 Muscles of Upper Extremities and Shoulder.

Copyright © 2010 Pearson Education, Inc.

Muscles of the Body Part C

• Adapted for H. Biology II 2014-2015

• Muscles of Upper Extremities and Shoulder


Muscles Crossing the Shoulder Joint

• Nine muscles cross the shoulder joint to insert on and move the humerus



• 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



• 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. Figure 10.14a

Clavicle

Deltoid

Sternum

Pectoralis major

Lateral headLong headMedial head

CoracobrachialisTriceps brachii:

Biceps brachiiBrachialisBrachioradialis

(a) Anterior view

Copyright © 2010 Pearson Education, Inc. Figure 10.14b

Supraspinatus*Spine of scapula

(b) Posterior view

Deltoid (cut)Greater tubercleof humerusInfraspinatus*

Teres minor*

Teres major

Triceps brachii:

Latissimus dorsi

HumerusOlecranon processof ulna

Lateral head Long head

Anconeus

* Rotator cuff muscles


Clavicle

Deltoid

Sternum

Pectoralis major

Lateral headLong headMedial head

CoracobrachialisTriceps brachii:

Biceps brachiiBrachialisBrachioradialis

(a) Anterior view


Muscles Crossing the Elbow Joint

• Posterior extensor muscles

• Triceps brachii—prime mover of forearm extension

• Anconeus—weak synergist


Supraspinatus*Spine of scapula

(b) Posterior view

Deltoid (cut)Greater tubercleof humerusInfraspinatus*

Teres minor*

Teres major

Triceps brachii:

Latissimus dorsi

HumerusOlecranon processof ulna

Lateral head Long head

Anconeus

* Rotator cuff muscles


Tricepsbrachii

Lateralhead

Humerus

LongheadMedialhead

(a)

Brachialis

Short headLong head

(a) Muscles of the arm

Extensors

Flexors

Others

Posteriorcompartment

of arm (extendselbow); innervation:

radial nerve

Biceps brachii

Anterior compartment of arm (flexes elbow); innervation:musculocutaneous nerve


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



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



• Pronators: pronator teres and pronator quadratus

• Supinator: a synergist with the biceps brachii


Muscles of the Forearm: Anterior Compartment

• Flexors

• Flexor carpi radialis

• Palmaris longus

• Flexor carpi ulnaris

• Flexor digitorum muscles (superficialis and profundus)

• Flexor pollicis longus


Biceps brachii

Tendon of biceps brachii

Pronator teres

Brachioradialis

Extensor carpi radialis longus

Flexor pollicis longus

Pronator quadratus

Flexor retinaculum

Medial head oftriceps brachii

Medial epicondyleof humerus

Flexor carpi radialis

Palmar aponeurosis

Superficial transverseligament of palm

Palmaris longus

Flexor carpi ulnaris

Flexor digitorumsuperficialis

(a)

Copyright © 2010 Pearson Education, Inc. Figure 10.15c

Supinator

Tendon of flexorcarpi ulnaris (cut)

Tendon of flexordigitorum profundus

Flexor pollicis longus

Thenar muscles of thumb

Tendon of flexorpollicis longus

Lumbricals

Tendon of flexor digitorumsuperficialis (cut)

Pronator quadratus

Flexor digitorumprofundus

(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


Insertion oftriceps brachii

Anconeus

Flexor carpiulnaris

Extensor carpiulnaris

Extensor digitiminimi

Extensor indicis

Tendons of extensor carpiradialis brevis and longus

Extensorexpansion

(a)

Extensor pollicislongusExtensor pollicisbrevisAbductorpollicis longusExtensor digitorum

Extensor carpiradialis brevis

Extensor carpiradialis longus

Brachioradialis

Tendons ofextensordigitorum


Olecranon process of ulna

Interossei

Anconeus

Supinator

Abductor pollicis longus

Extensor pollicis longus

Extensor pollicis brevis

Extensor indicis

(b)


Extensors

Flexors

Others

(b)

Flexors

Extensors

Ulna

Posterior compartment of forearm(extends wrist and fingers);innervation: radial nerve

Others

Radius

Pronatorteres Brachioradialis(elbow flexor)

Abductorpollicis longus

(b) Muscles of the forearm

Anterior compartment of forearm (flexes wrist and fingers); innervation: median or ulnar nerve


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


Finger and Thumb Movements

• Flexion

• Thumb—bends medially along the palm

• Fingers—bend anteriorly

• Extension

• Thumb—points laterally

• Fingers—move posteriorly


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


Flexor digitorumprofundus

Tendons of:

Flexor digitorumsuperficialis

Thirdlumbrical

Fourthlumbrical

Opponensdigiti minimi

Flexor digitiminimi brevis

Abductordigiti minimi

Pisiform bone

Flexor carpiulnaris tendon

Flexor digitorumsuperficialistendons Flexor pollicis longus

Flexor carpi radialisPalmaris longus

Flexor retinaculum

Abductor pollicislongus

Opponens pollicis

Abductor pollicisbrevis

Flexor pollicisbrevis

Adductor pollicis

Dorsal interossei

First lumbrical

Second lumbrical

Fibrous sheath

(a) First superficial layer

Tendons of:


Flexor digitorumprofundus tendon

Flexor digitorumsuperficialis tendon

Palmar interossei

Opponens digitiminimi

Flexor digiti minimibrevis (cut)

Abductor digiti minimi(cut)

Flexor pollicis longustendon

Opponens pollicis

Abductor pollicisbrevis

Flexor pollicisbrevis

Adductor pollicis

Dorsal interossei

(b) Second layer