1. 10 The Muscular System C h a p t e r
PowerPoint® Lecture Slides prepared by Jason LaPres
Lone Star College - North Harris

2. An Introduction to the Muscular System
Consists only of skeletal muscles
Muscle Organization and Function
Muscle organization affects power, range, and speed of muscle movement
Fascicles
Muscle cells (fibers) are organized in bundles (fascicles)
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3. Fascicle Arrangement Classification of Skeletal Muscles
By the way fascicles are organized
By relationships of fascicles to tendons
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4. Fascicle Arrangement Organization of Skeletal Muscle Fibers
Four patterns of fascicle organization
Parallel
Convergent
Pennate
Circular
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5. Fascicle Arrangement Parallel Muscles
Fibers parallel to the long axis of muscle
For example, biceps brachii
Depends on total number of myofibrils
Directly relates to cross section of muscle
1 in.2 (6.45 cm2) of cross section develops 50 lb (23 kg) of tension
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6. Fascicle Arrangement [INSERT FIG. 11.1a]
Figure 10–1a Muscle Types Based on Pattern of Fascicle Organization.
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7. Fascicle Arrangement Convergent Muscles
A broad area converges on attachment site (tendon, aponeurosis, or raphe)
Muscle fibers pull in different directions, depending on stimulation
For example, pectoralis muscles
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8. Fascicle Arrangement [INSERT FIG. 11.1b]
Figure 10–1b Muscle Types Based on Pattern of Fascicle Organization.
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9. Fascicle Arrangement 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
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10. Fascicle Arrangement Pennate Muscles Unipennate Bipennate Multipennate
Fibers on one side of tendon
For example, extensor digitorum
Bipennate
Fibers on both sides of tendon
For example, rectus femoris
Multipennate
Tendon branches within muscle
For example, deltoid
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11. Fascicle Arrangement [INSERT FIG. 11.1c, d, e]
Figure 10–1c, d, e Muscle Types Based on Pattern of Fascicle Organization.
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12. Fascicle Arrangement Circular Muscles Also called sphincters
Open and close to guard entrances of body
For example, orbicularis oris muscle of the mouth
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13. Fascicle Arrangement
Figure 10–1f Muscle Types Based on Pattern of Fascicle Organization.
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14. Levers Skeletal Motion
Skeletal muscles attach to skeleton, produce motion
Type of muscle attachment affects power, range, and speed of muscle movement
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15. Levers
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)
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16. Levers Function of a lever is to change The Three Classes of Levers
Direction of an AF
Distance and speed of movement produced by an AF
Effective strength of an AF
The Three Classes of Levers
Depend on the relationship between applied force, fulcrum, and resistance
First class, second class, and third class
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17. Levers First-Class Lever Seesaw or teeter-totter is an example
Center fulcrum between applied force and resistance
Force and resistance are balanced
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18. Levers [INSERT FIG. 11.2a] Figure 10–2a The Three Classes of Levers.
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19. Levers Second-Class Levers Wheelbarrow is an example
Center resistance between applied force and fulcrum
A small force moves a large weight
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20. Levers [INSERT FIG. 11.2b] Figure 10–2b The Three Classes of Levers.
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21. Levers 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
First, Second, and Third-Class Levers
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22. Levers [INSERT FIG. 11.2c] Figure 10–2c The Three Classes of Levers.
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23. Muscle Attachments to Other Tissues
Origins and Insertions
Muscles have one fixed point of attachment (origin) and one moving point of attachment (insertion)
Most muscles originate or insert on the skeleton
Origin is usually proximal to insertion
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24. Muscle Attachments to Other Tissues
Actions
Movements produced by muscle contraction
Body movements
For example, flexion, extension, adduction, etc.
Described in terms of bone, joint, or region
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25. Muscle Attachments to Other Tissues
Muscle Interactions
Muscles work in groups to maximize efficiency
Smaller muscles reach maximum tension first, followed by larger, primary muscles
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26. Muscle Attachments to Other Tissues
Muscle Terminology Based on Function
Agonist (or 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)
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27. Muscle Attachments to Other Tissues
Muscle Opposition
Agonists and antagonists work in pairs:
When one contracts, the other stretches
Such as flexors–extensors, abductors–adductors, etc.
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28. Naming Skeletal Muscles
Names of Skeletal Muscles
Correct names of muscles include the term muscle
Exceptions
Platysma
Diaphragm
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29. Naming Skeletal Muscles
Descriptive Names for Skeletal Muscles
Location in the body
Origin and insertion
Fascicle organization
Relative position
Structural characteristics
Action
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30. Naming Skeletal Muscles
Location in the Body
Identifies body regions
For example, temporalis muscle
Origin and Insertion
First part of name indicates origin
Second part of name indicates insertion
For example, genioglossus muscle
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31. Naming Skeletal Muscles
Fascicle Organization
Describes fascicle orientation within muscle
i.e., rectus (straight), transversus, oblique
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32. Naming Skeletal Muscles
Relative Position
Externus (superficialis)
Visible at body surface
Internus (profundus)
Deep muscles
Extrinsic
Muscles outside an organ
Intrinsic
Muscles inside an organ
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33. Naming Skeletal Muscles
Structural Characteristics
Number of tendons
bi = 2, tri = 3
Shape
Trapezius, deltoid, rhomboid
Size
Many terms refer to muscle size
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34. Naming Skeletal Muscles
Descriptive Terms for Muscle Size
Longus = long
Longissimus = longest
Teres = long and round
Brevis = short
Magnus = large
Major = larger
Maximus = largest
Minor = small
Minimus = smallest
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35. Naming Skeletal Muscles
Action
Movements
For example, flexor, extensor, retractor
Occupations or habits
For example, risor = laughter
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36. Naming Skeletal Muscles
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37. Naming Skeletal Muscles
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38. Muscular System Overview
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
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39. Muscular System Overview
Figure 10–3a (Part 1 of 2) An Overview of the Major Skeletal Muscles.
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40. Muscular System Overview
Figure 10–3a (Part 2 of 2) An Overview of the Major Skeletal Muscles.
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41. Muscular System Overview
Figure 10–3b (Part 1 of 2) An Overview of the Major Skeletal Muscles.
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42. Muscular System Overview
Figure 10–3b (Part 2 of 2) An Overview of the Major Skeletal Muscles.
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43. Axial Musculature 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
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44. Axial Musculature Six 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
Muscles of mastication
Move the mandible
Muscles of the tongue
Names end in glossus
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45. Axial Musculature Six Muscle Groups of the Head and Neck
Muscles of the pharynx
Begin swallowing process
Anterior muscles of the neck
Control position of larynx
Depress the mandible
Support tongue and pharynx
3D Peel-Away of Muscles of the Head and Neck
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46. Axial Musculature Muscles of Facial Expression
Orbicularis oris: constricts the mouth opening
Buccinator: moves food around the cheeks
Muscles of the epicranium (scalp)
Buccinator
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47. Axial Musculature Muscles of Facial Expression
Muscles of the epicranium (scalp)
Temporoparietalis
Occipitofrontalis
Frontal and occipital bellies
Separated by epicranial aponeurosis
Platysma
Covers anterior surface of neck
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48. Axial Musculature Figure 10–4a Muscles of Facial Expression.
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49. Axial Musculature Figure 10–4b Muscles of Facial Expression.
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50. [INSERT Table. 11.2- please split onto 2 slides if necessary]
Axial Musculature
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51. [INSERT Table. 11.2- please split onto 2 slides if necessary]
Axial Musculature
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52. [INSERT Table. 11.2- please split onto 2 slides if necessary]
Axial Musculature
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53. Axial Musculature Six Extrinsic Eye Muscles (Extra ocular)
Inferior rectus
Medial rectus
Superior rectus
Lateral rectus
Inferior oblique
Superior oblique
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54. Axial Musculature Figure 10–5a,b Extrinsic Eye Muscles.
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55. Axial Musculature Figure 10–5c, d Extrinsic Eye Muscles.
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56. Axial Musculature
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57. Axial Musculature Muscles of Mastication Masseter Temporalis
The strongest jaw muscle
Temporalis
Helps lift the mandible
Pterygoid muscles
Positions mandible for chewing
Masseter
Temporalis
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58. Axial Musculature Figure 10–6a Muscles of Mastication.
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59. Axial Musculature [INSERT FIG. 11.6b]
Figure 10–6b Muscles of Mastication.
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60. Axial Musculature [INSERT Table. 11.4]
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61. Axial Musculature Muscles of the Tongue Palatoglossus Styloglossus
Originates at palate
Styloglossus
Originates at styloid process
Genioglossus
Originates at chin
Hypoglossus
Originates at hyoid bone
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62. Axial Musculature Figure 10–7 Muscles of the Tongue.
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63. Axial Musculature
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64. Axial Musculature Muscles of the Pharynx
Pharyngeal constrictor muscles
Move food into esophagus
Laryngeal elevator muscles
Elevate the larynx
Palatal muscles
Lift the soft palate
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65. Axial Musculature Figure 10–8 Muscles of the Pharynx.
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66. Axial Musculature
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67. Axial Musculature Anterior Muscles of the Neck Digastric Mylohyoid
From chin to hyoid
And hyoid to mastoid
Mylohyoid
Floor of the mouth
Geniohyoid
Between hyoid and chin
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68. Axial Musculature 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
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69. Axial Musculature Figure 10–9a Muscles of the Anterior Neck.
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70. Axial Musculature Figure 10–9b Muscles of the Anterior Neck.
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71. Axial Musculature
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72. Axial Musculature Muscles of the Vertebral Column
Spinal extensors or erector spinae muscles (superficial and deep)
Spinal flexors (transversospinalis)
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73. Axial Musculature Muscles of the Vertebral Column
Superficial Spinal Extensors
Spinalis group
Longissimus group
Iliocostalis group
Longissimus
Spinalis
Iliocostalis
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74. Axial Musculature Muscles of the Vertebral Column
Deep Spinal Extensors
Semispinalis group
Multifidus muscle
Interspinalis muscles
Intertransversarii muscles
Rotatores muscles
SemispinalisCapitus
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75. Axial Musculature [INSERT FIG. 11.10a]
Figure 10–10a Muscles of the Vertebral Column.
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76. Axial Musculature [INSERT FIG. 11.10c]
Figure 10–10c Muscles of the Vertebral Column.
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77. [INSERT Table. 11.8 (top portion)]
Axial Musculature
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78. [INSERT Table. 11.8 (middle portion)]
Axial Musculature
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79. Axial Musculature Muscles of the Vertebral Column Spinal flexors Neck
Longus capitis and longus colli
Rotate and flex the neck
Lumbar
Quadratus lumborum muscles
Flex spine and depress ribs
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80. Axial Musculature [INSERT FIG. 11.10b]
Figure 10–10b Muscles of the Vertebral Column.
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81. Axial Musculature [INSERT FIG. 11.10a]
Figure 10–10a Muscles of the Vertebral Column.
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82. [INSERT Table. 11.8 (bottom portion)]
Axial Musculature
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83. Axial Musculature Oblique and Rectus Muscles Lie within the body wall
Oblique muscles
Compress underlying structures
Rotate vertebral column
Rectus muscles
Flex vertebral column
Oppose erector spinae
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84. Axial Musculature Oblique Muscles Cervical region Thoracic region
Scalene muscles
Flex the neck
Thoracic region
Intercostal muscles (external and internal)
Respiratory movements of ribs
Transversus thoracis
Cross inner surface of ribs
Internal Intercostals
External Intercostals
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85. Axial Musculature Oblique Muscles
Abdominopelvic region (same pattern as thoracic)
External oblique muscles
Internal oblique muscles
Transversus abdominis
External Obliques
Transversus Abdominis
Internal Obliques
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86. Axial Musculature Rectus Muscles Rectus abdominis
Between xiphoid process and pubic symphysis
Divided longitudinally by linea alba
Divided transversely by tendinous inscriptions
Diaphragmatic muscle or diaphragm
Divides thoracic and abdominal cavities
Performs respiration
Rectus Abdominis
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87. Axial Musculature [INSERT FIG. 11.11a]
Figure 10–11a Oblique and Rectus Muscles and the Diaphragm.
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88. Axial Musculature [INSERT FIG. 11.11b]
Figure 10–11b Oblique and Rectus Muscles and the Diaphragm.
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89. Axial Musculature [INSERT FIG. 11.11c]
Figure 10–11c Oblique and Rectus Muscles and the Diaphragm.
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90. [INSERT Table. 11.9-please split onto 2 slides if necessary]
Axial Musculature
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91. [INSERT Table. 11.9-please split onto 2 slides if necessary]
Axial Musculature
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92. Axial Musculature Muscles of the Pelvic Floor
Functions of pelvic floor muscles
Support organs of pelvic cavity
Flex sacrum and coccyx
Control movement of materials through urethra and anus
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93. Axial Musculature Muscles of the Pelvic Floor Perineum
Muscular sheet forming the pelvic floor, divided into
Anterior urogenital triangle
Posterior anal triangle
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94. Axial Musculature Perineum 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
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95. Axial Musculature Muscles of the Pelvic Floor Perineum
Pelvic diaphragm
Deep muscular layer extending to pubis
Supports anal triangle
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96. Axial Musculature [INSERT FIG. 11.12a]
Figure 10–12a Muscles of the Pelvic Floor.
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97. Axial Musculature [INSERT FIG. 11.12b]
Figure 10–12b Muscles of the Pelvic Floor.
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98. [INSERT Table. 11.10-please split onto 2 slides if necessary]
Axial Musculature
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99. [INSERT Table. 11.10-please split onto 2 slides if necessary]
Axial Musculature
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