1. Chapter 9B: The Muscular System Muscle Organization & Function (Not Interactive)

2. Muscle Organization and Function
Muscle organization affects power, range, and speed of muscle movement
Muscle cells (fibers) are organized in bundles (fascicles)

3. Organization of Skeletal Muscle Fibers
4 patterns of fascicle organization:
parallel
convergent
pennate
circular

4. Parallel Muscles Fibers parallel to the long axis of muscle
e.g., biceps brachii

5. Parallel Muscle Body
The center or body of the muscle thickens when parallel muscle contracts
Parallel muscles contract about 30%

6. Convergent Muscles
Figure 11–1b

7. Convergent Muscles
A broad area converges on attachment site (tendon, aponeurosis, or raphe)
Muscle fibers pull in different directions, depending on stimulation
e.g., pectoralis muscles

8. Pennate Muscles
Figure 11–1c, d, e

9. Pennate Muscles Unipennate: Bipennate: Multipennate:
fibers on 1 side of tendon
e.g., extensor digitorum
Bipennate:
fibers on both sides of tendon
e.g., rectus femoris
Multipennate:
tendon branches within muscle
e.g., deltoid

10. Pennate Muscles Form an angle with the tendon
Do not move as far as parallel muscles
Contain more myofibrils than parallel muscles
Develop more tension than parallel muscles

11. Circular Muscles
Figure 11–1f

12. Circular Muscles Also called sphincters
Open and close to guard entrances of body
e.g., obicularis oris

13. Levers Mechanically, each bone is a lever (a rigid, moving structure):
and each joint a fulcrum (a fixed point)
Muscles provide applied force (AF):
required to overcome resistance (R)

14. Functions of a Lever To change: direction of an AF
distance and speed of movement produced by an AF
effective strength of an AF

15. 3 Classes of Levers
Depend on the relationship between applied force, fulcrum, and resistance:
first class
second class
third class

16. First-Class Levers Seesaw is an example
Center fulcrum between applied force and resistance
Force and resistance are balanced

17. Second-Class Levers Wheelbarrow is an example
Center resistance between applied force and fulcrum
A small force moves a large weight

18. Third-Class Levers Most common levers in the body
Center applied force between resistance and fulcrum
Greater force moves smaller resistance
Maximizes speed and distance traveled

19. Origins and Insertions
Muscles have 1 fixed point of attachment (origin) and 1 moving point of attachment (insertion)
Most muscles originate or insert on the skeleton
Origin is usually proximal to insertion

20. Actions Movements produced by muscle contraction Body movements
e.g., flexion, extension, adduction, etc.
Described in terms of bone, joint, or region

21. Muscle Interactions Muscles work in groups to maximize efficiency
Smaller muscles reach maximum tension first, followed by larger, primary muscles

22. Muscle Terminology Based on Function
Agonist (prime mover):
produces a particular movement
Antagonist:
opposes movement of a particular agonist
Synergist:
a smaller muscle that assists a larger agonist
helps start motion or stabilize origin of agonist (fixator)

23. Muscle Opposition Agonists and antagonists work in pairs:
when 1 contracts, the other stretches
i.e., flexors–extensors, abductors–adductors, etc.

24. Names of Skeletal Muscles
Correct names of muscles include the term muscle
Exceptions:
platysma
Diaphragm
****STUDY THE DIAGRAMS ON THE NEXT 2 SLIDES FOR THE QUIZ***

25. Naming Skeletal Muscles
Table 11–1 (1 of 2)

26. Naming Skeletal Muscles
Table 11–1 (2 of 2)

27. Descriptive Names for Skeletal Muscles
Location in the body
Origin and insertion
Fascicle organization
Relative position
Structural characteristics
Action

28. Location in the Body
Identifies body regions:
e.g., temporalis muscle

29. Origin and Insertion First part of name indicates origin
Second part of name indicates insertion:
e.g., genioglossus muscle

30. Fascicle Organization
Describes fascicle orientation within muscle:
i.e., rectus (straight), transversus, oblique

31. Relative Position Externus (superficialis): Internus (profundus):
visible at body surface
Internus (profundus):
deep muscles
Extrinsic:
muscles outside an organ
Intrinsic:
muscles inside an organ

32. Structural Characteristics
Number of tendons:
bi = 2, tri = 3
Shape:
trapezius, deltoid, rhomboid
Size

33. Names for Muscle Size (1 of 2)
Longus = long
Longissimus = longest
Teres = long and round
Brevis = short
Magnus = large

34. Names For Muscle Size (2 of 2)
Major = larger
Maximus = largest
Minor = small
Minimus = smallest

35. Action Movements: Occupations or habits:
e.g., flexor, extensor, retractor
Occupations or habits:
e.g., risor = laughter

36. Ch. 11 Notes Axial and Appendicular Muscles Part I: Face and Neck
Figure 11–3a

37. Axial and Appendicular Muscles
Figure 11–3b

38. Divisions of the Muscular System
Axial muscles:
position head and spinal column
move rib cage
60% of skeletal muscles
Appendicular muscles:
support pectoral and pelvic girdles
support limbs
40% of skeletal muscles

39. The Axial Muscles Divisions based on location and function:
muscles of head and neck
muscles of vertebral column
oblique and rectus muscles
muscles of pelvic floor

40. 6 Muscle Groups of the Head and Neck
Muscles of facial expression:
originate on skull
Extrinsic eye muscles:
originate on surface of orbit
control position of eye

41. 6 Muscle Groups of the Head and Neck
Muscles of mastication:
move the mandible
Muscles of the tongue:
names end in glossus
Muscles of the pharynx:
begin swallowing process

42. 6 Muscle Groups of the Head and Neck
Anterior muscles of the neck:
control position of larynx
depress the mandible
support tongue and pharynx

43. Muscles of Facial Expression
Orbicularis oris:
constricts the mouth opening
Buccinator:
moves food around the cheeks
Muscles of the epicranium (scalp)

44. Muscles of Facial Expression
Figure 11–4b

45. Muscles of the Epicranium (Scalp)
Temporoparietalis
Occipitofrontalis:
frontal and occipital bellies
separated by epicranial aponeurosis
Platysma:
covers anterior surface of neck

46. Muscles of Facial Expression
Figure 11–4a

47. Extrinsic Eye Muscles
Also called extra-ocular muscles
Figure 11–5a, b

48. 6 Extrinsic Eye Muscles Inferior rectus Medial rectus Superior rectus
Lateral rectus
Inferior oblique
Superior oblique

49. 3 Muscles of Mastication
Masseter:
the strongest jaw muscle
Temporalis:
helps lift the mandible
Pterygoid muscles:
position mandible for chewing

50. Muscles of Mastication
Figure 11–6

51. 4 Muscles of the Tongue Palatoglossus: Styloglossus: Genioglossus:
originates at palate
Styloglossus:
originates at styloid process
Genioglossus:
originates at chin
Hypoglossus:
originates at hyoid bone

52. Muscles of the Tongue
Figure 11–7

53. 3 Muscles of the Pharynx Pharyngeal constrictor muscles:
move food into esophagus
Laryngeal elevator muscles:
elevate the larynx
Palatal muscles:
lift the soft palate

54. Muscles of the Pharynx
Figure 11–8

55. 6 Anterior Muscles of the Neck
Digastric:
from chin to hyoid
and hyoid to mastoid
Mylohyoid:
floor of the mouth
Geniohyoid:
between hyoid and chin

56. 6 Anterior Muscles of the Neck
Stylohyoid:
between hyloid and styloid
Sternocleidomastoid:
from clavicle and sternum to mastoid
Omohyoid:
attaches scapula, clavicle, first rib, and hyoid

57. Anterior Muscles of the Neck
Figure 11–9

58. Ch.11 Axial/Appendicular Muscles Part II: Muscles of the Vertebral Column
Figure 11–10a

59. Muscles of the Vertebral Column
Spinal extensors or erector spinae muscles (superficial and deep)
Spinal flexors (transversospinalis)

60. Muscles of the Vertebral Column
Figure 11–10b, c

61. Superficial Spinal Extensors
Spinalis group
Longissimus group
Iliocostalis group

62. Deep Spinal Extensors Semispinalis group Multifidus muscle
Interspinalis muscles
Intertransversarii muscles
Rotatores muscles

63. Spinal Flexors Neck: Lumbar: longus capitis and longus colli
rotate and flex the neck
Lumbar:
quadratus lumborum muscles
flex spine and depress ribs

64. Oblique and Rectus Muscles
Lie within the body wall
Figure 11–11a, b

65. Oblique and Rectus Muscles
Oblique muscles:
compress underlying structures
rotate vertebral column
Rectus muscles:
flex vertebral column
oppose erector spinae

66. Oblique Muscles
Cervical region:
scalene muscles
flex the neck

67. Oblique Muscles Thoracic region:
intercostal muscles (external and internal intercostals):
respiratory movements of ribs
transversus thoracis:
cross inner surface of ribs

68. Oblique Muscles Abdominopelvic region (same pattern as thoracic):
external oblique muscles
internal oblique muscles
Transversus abdominis

69. Oblique and Rectus Muscles
Figure 11–11a, c

70. Rectus Group Rectus abdominis:
between xiphoid process and pubic symphysis
divided longitudinally by linea alba
divided transversely by tendinous inscriptions

71. Rectus Group Diaphragmatic muscle or diaphragm:
divides thoracic and abdominal cavities
performs respiration

72. Functions of Pelvic Floor Muscles
Support organs of pelvic cavity
Flex sacrum and coccyx
Control movement of materials through urethra and anus

73. Perineum Muscular sheet forming the pelvic floor, divided into:
anterior urogenital triangle
posterior anal triangle

74. Muscles of the Pelvic Floor
Figure 11–12a

75. Urogenital Diaphragm Deep muscular layer between pubic bones:
supports the pelvic floor
and muscles of the urethra
Superficial muscles of the urogenital triangle:
support external genitalia

76. Pelvic Diaphragm Deep muscular layer extending to pubis:
supports anal triangle

77. Muscles of the Pelvic Floor
Figure 11–12b

78. What are the principal appendicular muscles of the body and their origins, insertions, actions, and innervations?

79. Ch.11 Muscle Notes: Part III The Appendicular Muscles
Figure 11–13a

80. The Appendicular Muscles
Figure 11–13b

81. The Appendicular Muscles
Position and stabilize pectoral and pelvic girdles
Move upper and lower limbs

82. Muscles of the Shoulders and Upper Limbs
Position the pectoral girdle
Move the arm
Move the forearm and hand
Move the hand and fingers

83. Muscles that Position the Pectoral Girdle
3D Peel-Away of Muscles of the Pectoral Girdle
PLAY
Figure 11–14a

84. Muscles that Position the Pectoral Girdle
Figure 11–14b

85. 6 Muscles that Position the Pectoral Girdle (1 of 4)
Trapezius:
superficial
covers back and neck to base of skull
inserts on clavicles and scapular spines

86. 6 Muscles that Position the Pectoral Girdle (2 of 4)
Rhomboid and levator scapulae:
deep to trapezius
attach to cervical and thoracic vertebrae
insert on scapular border

87. 6 Muscles that Position the Pectoral Girdle (3 of 4)
Serratus anterior:
on the chest
originates along ribs
inserts on anterior scapular margin

88. 6 Muscles that Position the Pectoral Girdle (4 of 4)
Subclavius:
originates on ribs
inserts on clavicle
Pectoralis minor:
attaches to scapula

89. Muscles that Move the Arm
Figure 11–15a

90. Muscles that Move the Arm
Figure 11–15b

91. 9 Muscles that Move the Arm (1 of 3)
Deltoid:
the major abductor
Supraspinatus:
assists deltoid
Subscapularis and teres major:
produce medial rotation at shoulder
PLAY
3D Rotation: Muscles of the Arm

92. 9 Muscles that Move the Arm (2 of 3)
Infraspinatus and teres minor:
produce lateral rotation at shoulder
Coracobrachialis:
attaches to scapula
produces flexion and adduction at shoulder

93. 9 Muscles that Move the Arm (3 of 3)
Pectoralis major:
between anterior chest and greater tubercle of humerus
produces flexion at shoulder joint
Latissimus dorsi:
between thoracic vertebrae and humerus
produces extension at shoulder joint

94. The Rotator Cuff Muscles involved in shoulder rotation
supraspinatus, subscapularis, infraspinatus, teres minor,and their tendons

95. Muscles that Move the Forearm and Hand
Figure 11–16a

96. Muscles that Move the Forearm and Hand
Figure 11–16b

97. Muscles that Move the Forearm and Hand
Originate on humerus and insert on forearm
Exceptions:
the major flexor (biceps brachii)
the major extensor (triceps brachii)
3D Rotation: Muscles of the
Forearm and Hand
PLAY

98. Extensors and Flexors Extensors: Flexors:
mainly on posterior and lateral surfaces of arm
Flexors:
mainly on anterior and medial surfaces

99. 13 Muscles that Move the Forearm and Hand (1 of 8)
Biceps brachii:
flexes elbow
stabilizes shoulder joint
originates on scapula
inserts on radial tuberosity

100. 13 Muscles that Move the Forearm and Hand (2 of 8)
Triceps brachii:
extends elbow
originates on scapula
inserts on olecranon
Brachialis and brachioradialis:
flex elbow

101. 13 Muscles that Move the Forearm and Hand (3 of 8)
Anconeus:
opposes brachialis
Palmaris longus:
superficial
flexes wrist

102. 13 Muscles that Move the Forearm and Hand (4 of 8)
Flexor carpi ulnaris:
superficial
flexes wrist
adducts wrist

103. 13 Muscles that Move the Forearm and Hand (5 of 8)
Flexor carpi radialis:
superficial
flexes wrist
abducts wrist

104. 13 Muscles that Move the Forearm and Hand (6 of 8)
Extensor carpi radialis:
superficial
extends wrist
abducts wrist

105. 13 Muscles that Move the Forearm and Hand (7 of 8)
Extensor carpi ulnaris:
superficial
extends wrist
adducts wrist

106. 13 Muscles that Move the Forearm and Hand (8 of 8)
Pronator teres and supinator:
originate on humerus and ulna
rotate radius
Pronator quadratus:
originates on ulna
assists pronator teres

107. Muscles that Move the Hand and Fingers
Figure 11–17a, b

108. Muscles that Move the Hand and Fingers
Figure 11–17c, d

109. Muscles of the Pelvis and Lower Limbs
Pelvic girdle is tightly bound to axial skeleton:
permits little movement
has few muscles

110. Muscles that Position the Lower Limbs
Muscles that move the thigh
Muscles that move the leg
Muscles that move the foot and toes

111. Muscles that Move the Thigh
Figure 11–19a, b

112. Muscles that Move the Thigh
Figure 11–19c, d

113. Muscles that Move the Thigh
Gluteal muscles
Lateral rotators
Adductors
Iliopsoas
PLAY
3D Peel-Away of Muscles of the Thigh
PLAY
3D Peel-Away of Rectus Muscle

114. Gluteal Muscles (1 of 2) Cover lateral surfaces of ilia
Gluteus maximus:
largest, most posterior gluteal muscle
produces extension and lateral rotation at hip

115. Gluteal Muscles (2 of 2) Tensor fasciae latae:
works with gluteus maximus
stabilizes iliotibial tract
Gluteus medius and gluteus minimus:
originate anterior to gluteus maximus
insert on trochanter

116. Lateral Rotators
Group of 6 muscles, including:
piriformis
obturator

117. Adductors (1 of 2) Adductor magnus: Adductor brevis: Adductor longus:
produces adduction, extension, and flexion
Adductor brevis:
hip flexion and adduction
Adductor longus:

118. Adductors (2 of 2)
Pectineus:
hip flexion and adduction
Gracilis:

119. Iliopsoas
2 hip flexors insert on the same tendon:
psoas major
iliacus

120. Muscles that Move the Leg
Figure 11–20a

121. Muscles that Move the Leg
Figure 11–20b, c

122. Muscles that Move the Leg
Flexors of the knee:
originate on the pelvic girdle
Extensors of the knee:
originate on the femoral surface
insert on the patella

123. Flexors of the Knee Biceps femoris Semimembranosus Semitendinosus
Sartorius:
originates superior to the acetabulum
Popliteus:
rotates the tibia to unlock the knee

124. Hamstrings
Made up of:
biceps femoris
semimembranosus
semitendinosus

125. Extensors of the Knee 4 muscles of the quadriceps femoris:
3 vastus muscles
rectus femoris muscle

126. Muscles that Move the Foot and Toes
Figure 11–21a, b

127. Muscles that Move the Foot and Toes
Figure 11–21c, d

128. Muscles that Move the Foot and Toes
Extrinsic muscles that move the foot and toes include:
muscles that produce extension at the ankle
muscles that produce flexion at the ankle
muscles that produce extension at the toes
muscles that produce flexion at the toes

129. 4 Muscles that Produce Extension at the Ankle
Gastrocnemius
Soleus
Fibularis
Tibialis posterior
PLAY
3D Peelaway of Muscles of the Leg and Foot

130. The Achilles Tendon The calcaneal tendon (Achilles tendon):
shared by the gastrocnemius and soleus

131. Muscles that Produce Flexion at the Ankle
Tibialis anterior:
opposes the gastrocnemius