The Muscles of the Upper Extremity

- A Visual Guide -

Anatomy & Physiology I

BIOL 121

Rob Swatski

Associate Professor of Biology

HACC - York Campus

Frontalis

Draws back scalp, wrinkles forehead,

raises eyebrows 2

Frontalis

3

Occipitalis

Draws back scalp, wrinkles forehead 4

Auricularis anterior

Moves the ear 5

Orbicularis oculi

Closes eyelids; used in blinking,

winking, and squinting 6

Orbicularis oculi

7

Zygomaticus major

Draws angles of mouth upward

and outward; major muscle

used in smiling and laughing 8

Zygomaticus major

9

Zygomaticus major

10

Orbicularis oris

Closes and protrudes lips;

the "kissing muscle“; used

in whistling and forming many letters

during speech 11

Orbicularis oris

12

Risorius

Draws angles of mouth

laterally; used in grinning 13

Depressor anguli oris (Triangularis)

Draws angles of mouth

downward and laterally when

opening mouth; used in

frowning 14

Depressor anguli oris (Triangularis)

15

Buccinator

Draws angles of mouth laterally;

compresses cheek;

used to create

sucking action 16

Mentalis

Elevates and protrudes lower lip;

used in pouting 17

Platysma

http://commons.wikimedia.org/wiki/File:Platysma.png

Draws down lower lip and angles of mouth; tenses skin of the neck; helps depress mandible 18

Masseter

Elevates mandible

when chewing and slightly protracts it 19

Masseter

20

Temporalis

Elevates, retracts, and assists in side-to-side movement of mandible 21

Genioglossus

http://commons.wikimedia.org/wiki/File:Genioglossus.png

Protracts and depresses tongue 22

Styloglossus

http://commons.wikimedia.org/wiki/File:Styloglossus.png

Retracts and elevates tongue 23

Stylohyoid

http://commons.wikimedia.org/wiki/File:Musculi_colli_stylohyoideus.svg

Retracts and elevates the hyoid bone 24

Sternocleidomastoid

Contraction of one side: laterally flexes neck, rotates head to opposite side Contraction of both sides together: flexes neck 25

Sternocleidomastoid

26

Semispinalis capitis

Extends head and rotates it to opposite side 27

Splenius capitis

Extends and hyperextends head; Contraction of only one side laterally flexes and rotates head and neck 28

Splenius capitis

29

Trapezius

Elevates, depresses,

retracts, and rotates scapula;

rotates arm 30

Trapezius

31

Trapezius

32

Latissimus dorsi

Extends, adducts, and medially rotates arm;

draws shoulder downward and

backward 33

Latissimus dorsi

34

Pectoralis major

Adducts and medially rotates arm; flexes and

extends humerus 35

Pectoralis major

36

Serratus anterior

Abducts and protracts scapula 37

Serratus anterior

38

Deltoid

Flexes, medially rotates, and abducts arm 39

Coracobrachialis Flexes and adducts humerus

40

Coracobrachialis

41

Supraspinatus

Abducts arm; stabilizes head of humerus in glenoid cavity; one of the "rotator cuff" muscles 42

Infraspinatus

Laterally rotates shoulder; stabilizes head of humerus in glenoid cavity; one of the "rotator cuff" muscles 43

Teres minor

Laterally rotates arm; one of the "rotator cuff" muscles 44

Teres major

Medially rotates and adducts arm 45

Biceps brachii

Flexes and supinates forearm 46

Biceps brachii

47

Brachialis

Flexes elbow 48

Triceps brachii

Extends forearm 49

Triceps brachii

50

Anconeus

Extends forearm and stabilizes elbow joint

51

Anconeus

52

Brachioradialis Flexes elbow

53

Pronator teres Pronates forearm and

assists in flexing elbow

54

Flexor carpi radialis Flexes wrist and abducts hand

55

Palmaris longus

Flexes wrist

56

Flexor carpi ulnaris

Flexes and adducts wrist

57

Extensor carpi radialis longus

Extends wrist and abducts hand

58

Extensor digitorum

Extends fingers and wrist

59

External intercostals

Elevates rib cage 60

Internal intercostals

Draws ribs together and depresses rib cage 61

Pectoralis minor

Elevates 3rd-5th ribs during forced inspiration 62

Diaphragm

Flattens on contraction,

increasing volume of

thorax during inspiration 63

External oblique

Compresses abdomen; laterally flexes and rotates vertebral column 64

External oblique

65

Internal oblique

Compresses abdomen; laterally flexes and rotates vertebral column 66

Transversus abdominis

Constricts abdomen and supports abdominal viscera 67

Transversus abdominis

68

Rectus abdominis

Compresses abdominal cavity and flexes vertebral column 69

Quadratus lumborum

Flexes lumbar region of vertebral

column laterally to the same

side; stabilizes and extends

lumbar vertebrae 70

Quadratus lumborum

71

Spinalis group of erector spinae

http://commons.wikimedia.org/wiki/File:Spinalis.png Extends vertebral column 72

Longissimus group of erector spinae

Extends and laterally flexes vertebral column 73

Iliocostalis group of erector spinae

http://commons.wikimedia.org/wiki/File:Longissimus.png

Extends and laterally flexes vertebral column 74

Levator ani

http://commons.wikimedia.org/wiki/File:Levator_ani.png

Forms floor of pelvic cavity; assists in defecation 75

Anconeus: 51-52 Auricularis anterior: 5 Biceps brachii: 46-47 Brachialis: 48 Brachioradialis: 53 Buccinator: 16 Coracobrachialis: 40-41 Deltoid: 39 Depressor anguli oris: 14-15 Diaphragm: 63 Extensor carpi radialis longus: 58 Extensor digitorum: 59 External intercostals: 60 External oblique: 64-65 Flexor carpi radialis: 55 Flexor carpi ulnaris: 57 Frontalis: 2-3 Genioglossus: 22 Iliocostalis group of erector spinae: 74 Infraspinatus: 43 Internal intercostals: 61 Internal oblique: 66 Latissimus dorsi: 33-34 Levator ani: 75 Longissimus group of erector spinae: 73 Masseter: 19-20 Mentalis: 17

Occipitalis: 4 Orbicularis oculi: 6-7 Orbicularis oris: 11-12 Palmaris longus: 56 Pectoralis major: 35-36 Pectoralis minor: 62 Platysma: 18 Pronator teres: 54 Quadratus lumborum: 70-71 Rectus abdominis: 69 Risorius: 13 Semispinalis capitis: 27 Serratus anterior: 37-38 Spinalis group of erector spinae: 72 Splenius capitis: 28-29 Sternocleidomastoid: 25-26 Styloglossus: 23 Stylohyoid: 24 Supraspinatus: 42 Temporalis: 21 Teres major: 45 Teres minor: 44 Transversus abdominis: 67-68 Trapezius: 30-32 Triceps brachii: 49-50 Zygomaticus major: 8-10

INDEX

Credits All photographs and labels by Rob Swatski, 2009-2012

http://robswatski.virb.com

This work bears an Attribution-Noncommercial Share Alike Creative Commons license.

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