1. 11 The Muscular System C h a p t e r
PowerPoint® Lecture Slides prepared by Jason LaPres
Lone Star College - North Harris
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2009 Pearson Education, Inc.,
publishing as Pearson Benjamin Cummings

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
Directly relates to cross section of muscle
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6. 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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7. Fascicle Arrangement Pennate Muscles Form an angle with the tendon
Do not move as far as parallel muscles
Develop more tension than parallel muscles
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8. 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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9. 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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10. 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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11. 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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12. Muscle Attachments to Other Tissues
Actions
Movements produced by muscle contraction
- All muscles pull; no muscles push
Body movements
For example, flexion, extension, adduction, etc.
Described in terms of bone, joint, or region
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13. Movements - From chapter 9
Angular Motion
Flexion
Angular motion
Anterior–posterior plane
Reduces angle between elements
Extension
Increases angle between elements
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14. Movements Angular Motion Hyperextension Angular motion
Extension past anatomical position
Angular Movements
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15. Movements Angular Motion Abduction Adduction Angular motion
Frontal plane
Moves away from longitudinal axis
Adduction
Moves toward longitudinal axis
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16. Movements Angular Motion Circumduction
Circular motion without rotation
Angular motion
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17. Movements Types of Movement Rotation
Direction of rotation from anatomical position
Relative to longitudinal axis of body
Left or right rotation
Medial rotation (inward rotation):
rotates toward axis
Lateral rotation (outward rotation):
rotates away from axis
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18. Movements Types of Movements Rotation Pronation: Supination:
rotates forearm, radius over ulna
Supination:
forearm in anatomical position
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19. Movements Types of Movements Special movements Inversion: Eversion:
twists sole of foot medially
Eversion:
twists sole of foot laterally
Dorsiflexion:
flexion at ankle (lifting toes)
Plantar flexion:
extension at ankle (pointing toes)
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20. Movements Special Movements Opposition
Thumb movement toward fingers or palm (grasping)
Protraction
Moves anteriorly
In the horizontal plane (pushing forward)
Retraction
Opposite of protraction
Moving posteriorly (pulling back)
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21. Movements Special Movements Elevation Depression Lateral flexion
Moves in superior direction (up)
Depression
Moves in inferior direction (down)
Lateral flexion
Bends vertebral column from side to side
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22. Muscle Attachments to Other Tissues - chpt 11
Muscle Interactions
Muscles work in groups to maximize efficiency
Smaller muscles reach maximum tension first, followed by larger, primary muscles
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23. 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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24. 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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25. 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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26. 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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27. Naming Skeletal Muscles
Fascicle Organization
Describes fascicle orientation within muscle
i.e., rectus (straight), transversus, oblique
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28. 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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29. 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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30. 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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31. Naming Skeletal Muscles
Action
Movements
For example, flexor, extensor, retractor
Occupations or habits
For example, risor = laughter
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32. 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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33. 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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34. Axial Musculature Muscles of Facial Expression
Orbicularis oris: constricts the mouth opening
Muscles of the epicranium (scalp)
Buccinator
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35. 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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36. Axial Musculature Muscles of Mastication Masseter Temporalis
The strongest jaw muscle
prime mover
Temporalis
Helps lift the mandible
synergist with the masseter
Masseter
Temporalis
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37. Axial Musculature Anterior Muscles of the Neck Sternocleidomastoid
From clavicle and sternum to mastoid
aka “the prayer muscle”
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38. Axial Musculature Oblique and Rectus Muscles Lie within the body wall
Oblique muscles
Compress underlying structures
Rotate vertebral column
Rectus muscles
Flex vertebral column
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39. Axial Musculature Oblique Muscles Thoracic region
Intercostal muscles (external and internal)
Respiratory movements of ribs
Internal Intercostals
External Intercostals
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40. 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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41. 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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42. Appendicular Musculature
Position and stabilize pectoral and pelvic girdles
Move upper and lower limbs
Divisions of Appendicular Muscles
Muscles of the shoulders and upper limbs
Muscles of the pelvis and lower limbs
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43. Appendicular Musculature
Muscles of the Shoulders and Upper Limbs
Position the pectoral girdle
Move the arm
Move the forearm and hand
Move the hand and fingers
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44. Appendicular Musculature
Muscles That Position the Pectoral Girdle
Trapezius
Superficial
Covers back and neck to base of skull
Inserts on clavicles and scapular spines
Trapezius
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45. Appendicular Musculature
Muscles That Position the Pectoral Girdle
Serratus anterior
On the chest
Originates along ribs
Inserts on anterior scapular margin
Serratus Anterior
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46. Appendicular Musculature
Muscles That Position the Pectoral Girdle
Pectoralis minor
Attaches to scapula
Pectoralis Minor
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47. Appendicular Musculature
Muscles That Move the Arm
Deltoid
The major abductor
prime mover
Supraspinatus
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48. Appendicular Musculature
Muscles That Move the Arm
Pectoralis major
Between anterior chest and greater tubercle of humerus
Produces flexion at shoulder joint
prime mover
Latissimus dorsi
Between thoracic vertebrae and humerus
Produces extension at shoulder joint
Pectoralis Major
Latissimus Dorsi
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49. Appendicular Musculature
The Rotator Cuff
Muscles involved in shoulder rotation
Supraspinatus, subscapularis, infraspinatus, teres minor, and their tendons
Teres Minor
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50. Appendicular Musculature

51. Appendicular Musculature

52. Appendicular Musculature
Muscles That Move the Forearm and Hand
Extensors
Mainly on posterior and lateral surfaces of arm
Flexors
Mainly on anterior and medial surfaces
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53. Appendicular Musculature
Flexors of the Elbow
Biceps brachii
Flexes elbow
Stabilizes shoulder joint
Originates on scapula
Inserts on radial tuberosity
Brachialis and brachioradialis
Flex elbow
Biceps Brachii
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54. Appendicular Musculature
Extensors of the Elbow
Triceps brachii
Extends elbow
prime mover
Originates on scapula
Inserts on olecranon
aka “the boxer’s muscle”
Triceps Brachii
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55. Appendicular Musculature
Muscles of the Pelvis and Lower Limbs
Pelvic girdle is tightly bound to axial skeleton
Permits little movement
Has few muscles
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56. Appendicular Musculature
Muscles That Position the Lower Limbs
Muscles that move the thigh
Muscles that move the leg
Muscles that move the foot and toes
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57. Appendicular Musculature
Muscles That Move the Thigh
Gluteal muscles
Lateral rotators
Adductors
3D Peel-Away of Muscles of the Thigh
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58. Appendicular Musculature
Muscles That Move the Thigh: Gluteal Muscles
Cover lateral surfaces of ilia
Gluteus maximus - prime mover
Largest, most posterior gluteal muscle
Produces extension and lateral rotation at hip
Tensor fasciae latae
works with gluteus maximus
Stabilizes iliotibial tract
Gluteus medius and gluteus minimus
Originate anterior to gluteus maximus
Insert on trochanter
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59. Appendicular Musculature
Muscles That Move the Thigh: Adductors
Gracilis
Hip flexion and adduction
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60. Appendicular Musculature
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
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61. Appendicular Musculature
Flexors of the Knee
Hamstrings
Biceps femoris
Semimembranosus
Semitendinosus
Sartorius - aka “the tailor’s muscle”
Originates superior to the acetabulum
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62. Appendicular Musculature
Muscles That Move the Leg
Extensors of the knee
Four muscles of the quadriceps femoris
Three vastus muscles
Rectus femoris muscle
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63. Appendicular Musculature
Muscles That Produce Extension (plantar flexion) at the Ankle
Gastrocnemius - aka “the toe-dancer’s muscle”
Soleus
3D Peel-Away of Muscles of the Leg and Foot
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64. Appendicular Musculature
The Achilles Tendon
The calcaneal tendon (Achilles tendon)
Shared by the gastrocnemius and soleus
NOT A Muscle; therefore incapable of contracting to produce movement
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65. Appendicular Musculature
Muscles That Produce Flexion (Dorsiflexsion) at the Ankle
Tibialis anterior
Antagonist of the gastrocnemius
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66. Effects of Aging on the Muscular System
Skeletal muscle fibers become smaller in diameter
Skeletal muscles become less elastic
Develop increasing amounts of fibrous tissue (fibrosis)
Decreased tolerance for exercise
Decreased ability to recover from muscular injuries
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