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The muscular system PART A 1. Interactions of Skeletal Muscles  Skeletal muscles work together or in opposition  Muscles only pull (never push)  As.

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Presentation on theme: "The muscular system PART A 1. Interactions of Skeletal Muscles  Skeletal muscles work together or in opposition  Muscles only pull (never push)  As."— Presentation transcript:

1 The muscular system PART A 1

2 Interactions of Skeletal Muscles  Skeletal muscles work together or in opposition  Muscles only pull (never push)  As muscles shorten, the insertion generally moves toward the origin  Whatever a muscle (or group of muscles) does, another muscle (or group) “undoes 2

3 Muscle Classification: Functional Groups  Prime movers – provide the major force for producing a specific movement  Antagonists – oppose or reverse a particular movement  Synergists Add force to a movement Reduce undesirable or unnecessary movement 3

4 Muscle Classification: Functional Groups  Fixators – synergists that immobilize a bone or muscle’s origin 4

5 Names of skeletal muscles  Names give clues to muscle characteristics Location: femoris, temporalis, etc Fascicle organization: rectus, oblique, etc Relative position: profundus, superficialis, etc Structure: biceps, triceps, etc 5

6 Names of skeletal muscles Size: maximus, longus, etc Shape: trapezius, deltoid, etc Origin and insertion: sternocleidomastoid, etc Action: flexor, pronator, etc 6

7 Organization of skeletal muscle fibers  Parallel muscle  Convergent muscle  Pennate muscle Unipennate Bipennate Multipennate  Circular muscle (sphincter)  Fusiform 7

8 Arrangement of Fascicles 8

9 Muscles of the Head 9

10 10

11 Muscles of the Head  Facial expression muscles Orbicularis oris  O: maxilla and mandible  I: lips  A: compresses lips Buccinator  O: maxilla and mandible  I: orbicularis oris  A: compresses the cheek (whistling) 11

12 Muscles of the Head Occipitofrontalis muscles  Occipital O: occipital bone I: galea aponeurotic A: pulls the scalp posteriorly  Frontalis O: galea aponeurotic I: skin of the eyebrow A: raise the eyebrow 12

13 Muscles of the Head  Orbicularis oculi O: frontal and maxillary bones I: eyelid A: closes eyes  Corrugator supercilli O: frontal bone I: skin of eyebrow A: draws eyebrow inferiorly and medially 13

14 Muscles of the Head  Levator labii superioris O: zigomatic and maxilla bone I: upper lip A: raises upper lips  Depressor labii inferioris O: mandible I: lower lip A: pulls lower lip inferiorly 14

15 Muscles of the Head  Depressor anguli oris O: mandible I: angle of mouth A: pulls corner of mouth down and laterally  Mentalis O: mandible I: skin of chin A: protudes lower lip 15

16 Muscles of the Head  Zigomatics O: zigomatic bone I: corner the mouth A: smiling muscle  Risorius O: masseter I: angle of the mouth A: pulls corner of lips laterally 16

17 Muscles of Mastication 17

18 Muscles of Mastication 18

19 Muscles of Mastication  Masseter muscles O: zigomatic and maxilla bones I: mandible A: closes the jaw  Temporalis muscles O: temporal fossa I: mandible A: closes the jaw 19

20 Muscles of Mastication  Pterygoids O: sphenoid, palatine and maxillary bones I: mandible A: elevates mandible  Buccinator 20

21 Extrinsic muscles of the eye 21

22 Extrinsic muscles of the eye  Inferior and superior rectus muscles  Lateral and medial rectus muscles  Inferior oblique muscles Elevates the eye and turns it laterally  Superior oblique muscles Depresses the eye and turns it laterally 22

23 Figure 15.3c Summary of Cranial Nerves and Muscle Actions 23

24 Muscles of the Neck 24

25 Muscles of the Neck 25

26 Muscles of the Neck Platysma  O: fascia of chest and deltoid  I: mandible, skin, corner of the mouth  A: depresses mandible, pulls lip back and down Sternocleidomastoid  O: manubrium and clavicle  I: temporal and occipital bones  A: flexion forward of the neck 26

27 Muscles of the Neck  Scalenes – anterior, middle, posterior O: cervical vertebrae I: first 2 ribs A: elevates first 2 ribs  Digastric O: mandible and mastoid process I: hyoid A: elevates hyoid bone 27

28 Muscles of the Neck  Mylohyoid O: mandible I: hyoid bone A: elevates hyoid bone  Sternohyoid O: manubrium and clavicle I: hyoid bone A: depresses hyoid bone 28

29 Muscles of the Thorax  Muscles inserting on the scapula: Rhomboid muscles  O: vertebrae  A: adducts and stabilizes scapula Levator scapulae muscles  O: vertebrae  A: elevates scapula 29

30 Muscles of the Thorax 30

31 Muscles of the Thorax  Abductors of the shoulder joint: Deltoid muscles (major abductor)  O: clavicle and scapula  I: humerus Supraspinatus muscles  O: scapula  I: humerus 31

32 Muscles of the Thorax 32

33 Muscles of the Thorax  Lateral rotation of the shoulder joint: Infraspinatus muscles  O: scapula  I: humerus Teres minor muscles  O: scapula  I: humerus 33

34 Muscles of the Thorax  Medial rotators of the shoulder joint Teres major muscles  O: scapula  I: humerus (anterior surface) 34

35 Muscles of the Thorax 35

36 Muscles of the Thorax Origin on the ribs and insertion on the scapula: Serratus anterior muscles  A: fixates, protracts the scapula Pectoralis minor muscles  A: ribs fixed: moves scapula forward and inferiorly and with scapula fixed it moves up the rib cage 36

37 Muscles of the Thorax 37

38 Muscles of the Thorax  Flexion of the shoulder joint (agonist): Pectoralis major muscles  O: clavicle, sternum, ribs, external oblique muscle  I: humerus  Extension of the shoulder joint (agonist): Latissimus dorsi muscles  O: vertebrae, ribs, ilium  I: humerus 38

39 Muscles of the Thorax 39

40 Muscles of the Thorax 40

41 Muscles of respiration  External intercostal O: rib above I: rib below A: elevates rib cage  Internal intercostal O: rib below I: rib above A: depresses rib cage 41

42 Muscles of Respiration 42

43 Muscles of Respiration 43

44 Muscles of Respiration  Diaphragm O: ribs and its cartilage, sternum, vertebrae I: central tendon of the cartilage A: prime action in inspiration 44

45 Muscles of Respiration 45

46 Muscles of the Abdomen  Rectus abdominis O: pubis I: xiphoid process, ribs A: flexes vertebral column,increase abdominal pressure  External oblique O: ribs I: linea alba, ilium A: see above, helps trunk rotation and lateral flexion 46

47 Muscles of the Abdomen  Internal oblique O: lumbar fascia, ilium, inguinal ligament I: linea alba, pubis, ribs A: same as external oblique  Transversus abdominis O: ribs, inguinal ligament, ilium, lumbar fascia I: linea alba, pubis A: compresses abdominal content 47

48 Muscles of the Abdomen 48

49 Muscles of the Arm 49

50 Muscles of the Arm  Biceps brachii muscle O: scapula, shoulder joint I: radius A: agonist flexor of the elbow  Brachioradialis O: humerus I: radius A: synergists for flexion of the elbow 50

51 Muscles of the Arm  Brachialis O:humerus I: ulna A: synergist for flexion of the elbow 51

52 Muscles of the Arm  Triceps brachii muscle (long, lateral and medial heads) O: scapula, humerus I: ulna A: agonist extensor of the elbow 52

53 Muscles of the Arm 53

54 Rotator Cuff Muscles  supraspinatus, infraspinatus, teres minor, and subscapularis Function mainly to reinforce the capsule of the shoulder Secondarily act as synergists and fixators 54

55 Rotator Cuff Muscles 55

56 Rotator Cuff Muscles 56

57 Muscles of the forearm  Flexion of the wrist (O: humerus) Flexor carpi ulnaris  I: metacarpus and carpus Flexor carpi radialis  I: metacarpals Palmaris longus  I: palm of the hand 57

58 Muscles of the forearm 58

59 Muscles of the forearm  Extension of the wrist (O: humerus) Extensor carpi radialis  I: metacarpus Extensor carpi ulnaris  I: metacarpus 59

60 Muscles of the forearm 60

61 Muscles of the forearm  Pronation of the forearm (I: radius) Pronator teres muscle  O: humerus 61

62 Muscles of the forearm 62

63 Muscles that move the hand 63

64 Muscles that move the hand 64

65 Muscles of the pelvis and lower limb  Gluteal muscles (O: ilium; I: femur) Gluteus maximus  A: extension and lateral rotation of thigh Gluteus medius and minimus  A: abduction and medial rotation of thigh 65

66 Muscles of the pelvis and lower limb 66

67 Muscles of the pelvis and lower limb  Sartorios O: ilium I: tibia A: flexes the thigh and helps in crossing the leg  Adductors of the leg O: pubis I: femur 67

68 Muscles of the pelvis and lower limb  Gracilis O: pubis I: tibia A: adducts, flexes and medially rotates the thigh 68

69 Muscles of the pelvis and lower limb 69

70 Iliopsoas muscle  Formed from the merging of the psoas major and the iliacus muscles  O: ilium, vertebrae  I: femur  Flexor of the trunk, flexor of the leg 70

71 Muscles of the pelvis and lower limb 71

72 Muscles of the leg  Quadriceps (I: tibia; A: extends the knee) Rectus femoris  O: ilium Vastus medialis, intermedius, lateralis  O: femur 72

73 Muscles of the leg 73

74 Muscles of the leg  Tensor fasciae latae O: ilium I: fasciae latae A: flexes, abducts the thigh; tenses the fasciae latae 74

75 Muscles of the leg  The hamstrings (O: ischium; I: tibia; A: extend thigh, flexes knee) Biceps femoris muscles Semimembranosus muscles Semitendinosis muscles 75

76 Muscles of the leg 76

77 Muscles of the leg  Plantar flexion (I: calcaneal tendon) Gastrocnemius muscle  O: femur Soleus muscle  O: fibula and tibia  Eversion and plantar flexion Fibularis muscle  O: fibula  I: foot 77

78 Flexors of the knee  Popliteus muscle O: femur I: tibia A: unlocks the knee joint 78

79 Muscles of the leg 79

80 Muscles of the leg  Tibialis anterior O: tibia I: metatarsal and cuneiform bones A: dorsiflexion of the foot  Tibialis posterior O: tibia I: tarsal and metatarsal bones A: foot inversion 80

81 Muscles of the leg 81

82 Muscles of the leg 82

83 Muscles That Move the Toes  Extensors digitorum O: Tibia, fibula I: Digits A: Extends the digits 83

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