1. Chapter 5 The Skeletal System
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 5 The Skeletal System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. The Skeletal System Parts of the skeletal system
Bones (skeleton)
Joints
Cartilages
Ligaments (bone to bone)(tendon=bone to muscle)
Divided into two divisions
Axial skeleton
Appendicular skeleton – limbs and girdle
Slide 5.1
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4. Functions of Bones Support of the body Protection of soft organs
Movement due to attached skeletal muscles
Storage of minerals and fats
Blood cell formation
Slide 5.2
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5. Bones of the Human Body The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Homogeneous
Spongy bone
Small needle-like pieces of bone
Many open spaces
Figure 5.2b
Slide 5.3
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6. Classification of Bones
Long bones
Typically longer than wide
Have a shaft with heads at both ends
Contain mostly compact bone
Examples: Femur, humerus
Slide 5.4a
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7. Classification of Bones
Short bones
Generally cube-shape
Contain mostly spongy bone
Examples: Carpals, tarsals
Slide 5.4b
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8. Classification of Bones on the Basis of Shape
Figure 5.1
Slide 5.4c
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9. Classification of Bones
Flat bones
Thin and flattened
Usually curved
Thin layers of compact bone around a layer of spongy bone
Examples: Skull, ribs, sternum
Slide 5.5a
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10. Classification of Bones
Irregular bones
Irregular shape
Do not fit into other bone classification categories
Example: Vertebrae and hip
Slide 5.5b
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11. Classification of Bones on the Basis of Shape
Figure 5.1
Slide 5.5c
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12. Gross Anatomy of a Long Bone
Diaphysis
Shaft
Composed of compact bone
Epiphysis
Ends of the bone
Composed mostly of spongy bone
Figure 5.2a
Slide 5.6
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13. Structures of a Long Bone
Periosteum
Outside covering of the diaphysis
Fibrous connective tissue membrane
Sharpey’s fibers
Secure periosteum to underlying bone
Arteries
Supply bone cells with nutrients
Figure 5.2c
Slide 5.7
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14. Structures of a Long Bone
Articular cartilage
Covers the external surface of the epiphyses
Made of hyaline cartilage
Decreases friction at joint surfaces
Figure 5.2a
Slide 5.8a
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15. Structures of a Long Bone
Medullary cavity
Cavity of the shaft
Contains yellow marrow (mostly fat) in adults
Contains red marrow (for blood cell formation) in infants
Figure 5.2a
Slide 5.8b
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16. Changes in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
Slide 5.12
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17. Bone Growth
Epiphyseal plates allow for growth of long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified
Cartilage is broken down
Bone replaces cartilage
Slide 5.13a
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18. Bone Growth Bones are remodeled and lengthened until growth stops
Bones change shape somewhat
Bones grow in width
Slide 5.13b
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19. Long Bone Formation and Growth
Figure 5.4a
Slide 5.14a
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20. Types of Bone Cells Osteocytes Osteoblasts Osteoclasts
Mature bone cells
Osteoblasts
Bone-forming cells
Osteoclasts
Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
Slide 5.15
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21. Bone Fractures A break in a bone Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
Slide 5.16
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22. Common Types of Fractures
Table 5.2
Slide 5.17
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23. Repair of Bone Fractures
Hematoma (blood-filled swelling) is formed
Break is splinted by fibrocartilage to form a callus
Fibrocartilage callus is replaced by a bony callus
Bony callus is remodeled to form a permanent patch
Slide 5.18
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24. Stages in the Healing of a Bone Fracture
Figure 5.5
Slide 5.19
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25. The Axial Skeleton Forms the longitudinal part of the body
Divided into three parts
Skull
Vertebral column
Bony thorax
Slide 5.20a
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26. The Axial Skeleton Slide 5.20b Figure 5.6
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27. The Skull Two sets of bones Bones are joined by sutures
Cranium
Facial bones
Bones are joined by sutures
Only the mandible is attached by a freely movable joint
Slide 5.21a
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28. The Skull Slide 5.21b Figure 5.7
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29. Bones of the Skull Slide 5.22 Figure 5.11
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30. Human Skull, Superior View
Figure 5.8
Slide 5.23
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31. Human Skull, Inferior View
Figure 5.9
Slide 5.24
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32. Paranasal Sinuses
Hollow portions of bones surrounding the nasal cavity
Figure 5.10
Slide 5.25a
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33. Paranasal Sinuses Functions of paranasal sinuses Lighten the skull
Give resonance and amplification to voice
Figure 5.10
Slide 5.25b
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34. The Hyoid Bone
The only bone that does not articulate with another bone
Serves as a moveable base for the tongue
Figure 5.12
Slide 5.26
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35. The Fetal Skull
The fetal skull is large compared to the infants total body length
Figure 5.13
Slide 5.27a
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36. The Fetal Skull
Fontanelles – fibrous membranes connecting the cranial bones
Allow the brain to grow
Convert to bone within 24 months after birth
Figure 5.13
Slide 5.27b
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37. The Vertebral Column Vertebrae separated by intervertebral discs
The spine has a normal curvature
Each vertebrae is given a name according to its location
Figure 5.14
Slide 5.28
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38. Structure of a Typical Vertebrae
Figure 5.16
Slide 5.29
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39. The Bony Thorax Forms a cage to protect major organs Slide 5.31a
Figure 5.19a
Slide 5.31a
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40. The Bony Thorax Made-up of three parts Sternum Ribs Thoracic vertebrae
Figure 5.19a
Slide 5.31b
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41. The Appendicular Skeleton
Limbs (appendages)
Pectoral girdle
Pelvic girdle
Slide 5.32a
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42. The Appendicular Skeleton
Figure 5.6c
Slide 5.32b
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43. The Pectoral (Shoulder) Girdle
Composed of two bones
Clavicle – collarbone
Scapula – shoulder blade
These bones allow the upper limb to have exceptionally free movement
Slide 5.33
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44. Bones of the Shoulder Girdle
Figure 5.20a, b
Slide 5.34a
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45. Bones of the Upper Limb The arm is formed by a single bone Humerus
Figure 5.21a, b
Slide 5.35a
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46. Bones of the Upper Limb The forearm has two bones Ulna Radius
Figure 5.21c
Slide 5.35b
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47. Bones of the Upper Limb The hand Carpals – wrist Metacarpals – palm
Phalanges – fingers
Figure 5.22
Slide 5.36
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48. Bones of the Pelvic Girdle
Hip bones
Composed of three pair of fused bones
Ilium
Ischium
Pubic bone
The total weight of the upper body rests on the pelvis
Protects several organs
Reproductive organs
Urinary bladder
Part of the large intestine
Slide 5.37
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49. The Pelvis Slide 5.38a Figure 5.23a
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50. Gender Differences of the Pelvis
Figure 5.23c
Slide 5.39
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51. Bones of the Lower Limbs
The thigh has one bone
Femur – thigh bone
Figure 5.35a, b
Slide 5.40a
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52. Bones of the Lower Limbs
The leg has two bones
Tibia
Fibula
Figure 5.35c
Slide 5.40b
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53. Bones of the Lower Limbs
The foot
Tarsus – ankle
Metatarsals – sole
Phalanges – toes
Figure 5.25
Slide 5.41
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54. Joints

55. Classification of Joints
Functional classification
(Focuses on amount of movement)
Synarthroses (immovable joints)
Amphiarthroses (slightly movable joints)
Diarthroses (freely movable joints)
Structural classification
(Based on the material binding them and presence or absence of a joint cavity)
Bony fusion
Fibrous
Cartilagenous
Synovial

56. Structural Classification of Joints
Fibrous joints
Generally immovable
Cartilaginous joints
Immovable or slightly moveable
Synovial joints
Freely moveable
Slide 5.45
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57. Table of Joint Types Functional across Structural down Synarthroses
(immovable joints)
Amphiarthroses
(some movement)
Diarthroses
(freely movable)
Bony Fusion
Synostosis (frontal=metopic suture; epiphyseal lines)
Fibrous
Suture (skull only)
-fibrous tissue is continuous with periosteum
Gomphoses (teeth)
-ligament is periodontal ligament
Syndesmoses
-ligaments only between bones; here, short so some but not a lot of movement (example: tib-fib ligament)
-ligament longer (example: radioulnar interosseous membrane)
Cartilagenous
(bone united by cartilage only)
Synchondroses
-hyaline cartilage (examples: manubrium-C1, epiphyseal plates)
Sympheses
-fibrocartilage (examples: between discs, pubic symphesis
Synovial
Are all diarthrotic

58. Fibrous Joints
Bones united by fibrous tissue – synarthrosis or largely immovable.
Types
Sutures
Syndesmoses
Gomphoses
Figure 5.27d, e
Slide 5.46
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59. Sutures Only between bones of skull
Fibrous tissue continuous with periosteum
Ossify and fuse in middle age: now technically called “synostoses”= bony junctions

60. Syndesmoses In Greek: “ligament” Bones connected by ligaments only
Amount of movement depends on length of the fibers: longer than in sutures

61. Gomphoses Is a “peg-in-socket” Only example is tooth with its socket
Ligament is a short periodontal ligament

62. Cartilaginous Joints – mostly amphiarthrosis
Bones connected by cartilage
Examples
Pubic symphysis
Intervertebral joints
Figure 5.27b, c
Slide 5.47
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63. Cartilagenous joints Articulating bones united by cartilage
Lack a joint cavity
Not highly movable
Two types
Synchondroses (singular: synchondrosis)
Sympheses (singular: symphesis)

64. Synchondroses Literally: “junction of cartilage”
Hyaline cartilage unites the bones
Immovable (synarthroses)
Examples:
Epiphyseal plates
Joint between first rib’s costal cartilage and manubrium of the sternum

65. Sympheses Literally “growing together” Fibrocartilage unites the bones
Slightly movable (amphiarthroses)
Resilient shock absorber
Provide strength and flexibility
Hyaline cartilage on articular surfaces of bones to reduce friction
Examples
Intervertebral discs
Pubic symphysis of the pelvis

66. Synchondroses and sympheses
Also pubic symphsis

67. Synovial Joints Articulating bones are separated by a joint cavity
Synovial fluid is found in the joint cavity
Figure 5.27f–h
Slide 5.48
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68. Features of Synovial Joints- Diarthroses
Articular cartilage (hyaline cartilage) covers the ends of bones
Joint surfaces are enclosed by a fibrous articular capsule
Have a joint cavity filled with synovial fluid
Ligaments reinforce the joint
Slide 5.49
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69. The Synovial Joint Slide 5.51 Figure 5.28
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70. Types of Synovial Joints Based on Shape
Figure 5.29a–c
Slide 5.52a
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71. Types of Synovial Joints Based on Shape
Figure 5.29d–f
Slide 5.52b
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72. Inflammatory Conditions Associated with Joints
Bursitis – inflammation of a bursa usually caused by a blow or friction
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative diseases of joints
Over 100 different types
The most widespread crippling disease in the United States
Slide 5.53
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73. Clinical Forms of Arthritis
Osteoarthritis
Most common chronic arthritis
Probably related to normal aging processes
Rheumatoid arthritis
An autoimmune disease – the immune system attacks the joints
Symptoms begin with bilateral inflammation of certain joints
Often leads to deformities
Slide 5.54a
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76. Clinical Forms of Arthritis
Gouty Arthritis
Inflammation of joints is caused by a deposition of urate crystals from the blood
Can usually be controlled with diet
Slide 5.54b
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