Radiographic Anatomy. The Value of gross anatomy. Understanding the muscoloskeletal system, the various types of bones and joints,

1. CONVENTIONAL RADIOGRAPHY
Part 2
Lecture 2
REVIEW OF THE
MUSCULOSKELETAL SYSTEM
Nchanji NKRH Keneth
kennchanji@yahoo.com/ nkeh92@gmail.com
662695118/671459765
B.TECH/HPD MDIRT
Radiology Department
St. Louis University, Mile 3 Nkwen Bamenda
Level 200 MDI, 2016/2017 Academic Year
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2. INTRODUCTION
• This system consists of the bones of the
skeleton, joints and skeletal muscles that
ensure movement.
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3. Functions Of Bones
• They exert many functions including;
Mineral storage especially calcium phosphate
Provides attachment site for muscles and tendons
Provides the body framework
Form boundaries of cranial, thoracic and pelvic
cavities, protecting organs contained.
Haemopoiesis in red bone marrow
Allows body movement by forming joints moved by
muscles.
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4. Types of bones
• Classified based on shape; long, short, irregular and
flat bones.
Long Bones e.g. femur, tibia, humerus, etc
Short bones e.g. wrist bones (carpals)
Irregular bones e.g. vertebrae and some skull bones.
Flat bones e.g. sternum, ribs and most skull bones.
Sesamoid bone e.g. patella.
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5. 1. Long Bones
• Much longer than they are wide.
• All bones of the limbs except for the patella
(kneecap),
and the bones of the wrist and ankle.
• Consists of a shaft plus 2 expanded ends.
• Your finger bones are long bones even though
they’re very short – how can this be?
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6. 2. Short Bones
• Roughly cube shaped.
• Bones of the wrist (carpals) and the
ankle (tarsals).
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7. 3. Flat Bones
• Thin, flattened, and usually a bit curved.
• Scapulae, sternum, (shoulder blades),
ribs and most bones of the skull.
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8. 4. Irregular Bones
• Have weird shapes that fit none of the 3
previous classes.
• Vertebrae, hip bones, 2 skull bones
( sphenoid and the ethmoid bones).
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9. Bone structure
• Bones are organs. Thus, they are
composed of multiple tissue types.
composed of:
–Bone tissue (osseous tissue).
–Fibrous connective tissue.
–Cartilage.
–Vascular tissue.
–Lymphatic tissue.
–Adipose tissue.
–Nervous tissue.
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10. 5/31/2017 10

11. Long bone structure
• Made up
• Shaft is known as the diaphysis.
–Consists of a thick collar of compact bone
surrounding a central marrow cavity
•In adults, the marrow cavity contains fat -
yellow bone marrow.
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12. 5/31/2017 12

13. 5/31/2017 13

14. Expanded ends are epiphyses
Thin layer of compact bone covering an
interior of spongy bone.
Joint surface of each epiphysis is covered
with a type of hyaline cartilage known as
articular cartilage. It cushions the bone ends
and reduces friction during movement.
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15. 5/31/2017 15

16. • The external surface of the entire bone
except for the joint surfaces of the epiphyses
is covered by a double-layered membrane
known as the periosteum.
•the artery carry blood
enter the bone of the shaft via a nutrient
foramen.
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17. 5/31/2017 17

18. • Internal bone surfaces are covered with a
delicate connective tissue membrane
known as the endosteum.
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19. Structure of Short, Irregular, and Flat
Bones
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20. • Thin plates of periosteum-covered
compact bone on the outside and
endosteum-covered cancellous or spongy
bone within.
• Have no diaphysis or epiphysis because
they are not cylindrical.
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21. 5/31/2017 21

22. • Contain bone marrow between
their trabeculae, but no marrow
cavity.
• In flat bones, the internal spongy
bone layer is known as the diploë,
and the whole arrangement
resembles a stiffened sandwich.
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23. • All bones consist of
a dense, solid
outer layer known
as compact bone
and an inner layer
of spongy or
cancellous bone
Above: Note the relationship btwn the
compact and spongy bone.
Below: Close up of spongy bone.
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24. BONE TISSUE
• Bone tissue is a type of connective tissue, so it
must consist of cells plus a significant amount of
extracellular matrix.
• Bone cells:
1. Osteoblasts
• Bone-building cells.
• Found in both the periosteum and the
endosteum
• Secrete collagen and other constituents of
bone.
• Found in ossification centres of immature
bone
• Found at sites of fracture.5/31/2017 24

25. The blue arrows indicate the osteoblasts. The
yellow arrows indicate the bone matrix they’ve
just secreted.
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26. 2. Osteocytes
• As bone develops, osteoblast become
embedded in the newly formed bone,
and are called osteocytes.
• Mature bone cells.
• Responsible for maintaining the bone
tissue.
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27. 3. Osteoclasts
– Cells that digest bone matrix –
this process is called bone
resorption and is part of normal
bone growth, development,
maintenance, and repair.
– Concentrated in the endosteum.
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28. BONE DEVELOPMENT
• Osteogenesis (ossification) is the process of
bone tissue formation.
• In embryos this leads to the formation of the
bony skeleton.
• In children and young adults, ossification
occurs as part of bone growth.
• In adults, it occurs as part of bone remodeling
and bone repair.
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29. FORMATION OF THE BONY SKELETON
• Before week 8, the human embryonic
skeleton is made of fibrous membranes and
hyaline cartilage.
• After week 8, bone tissue begins to replace
the fibrous membranes and hyaline cartilage.
–The development of bone from a fibrous
membrane is called intramembranous
ossification.
–The replacement of hyaline cartilage with
bone is known as
endochondral ossification.5/31/2017 29

30. 5/31/2017 30

31. INTRAMEMBRANOUS OSSIFICATION
• Some bones of the skull (frontal, parietal,
temporal, and occipital bones), the facial
bones, the clavicles, the pelvis, the
scapulae, and part of the mandible are
formed by intramembranous ossification.
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32. Involves 4 steps:
1) Ossification center forms :
Osteoblasts lay down matrix in fibrous
connective tissue membrane which surrounds and
entraps them. Osteoblasts become osteocytes.
Cytoplasmic processes extend through, canaliculi.
2) Calcium and mineral salts deposited and matrix
calcifies
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33. 3) Matrix develops into trabeculae joints
to form spongy bone with red marrow
between
4) periosteum forms and deposits outer
layer of compact bone.
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34. 5/31/2017 34

35. ENDOCHONDRIAL OSSIFICATION
• Begins with the formation of a hyaline cartilage
model which will later be replaced by bone.
• Most bones in the body develop via this model.
• More complicated than intramembranous
because the hyaline cartilage must be broken
down as ossification proceeds.
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36. 5/31/2017 36

37. • – Nutrient artery penetrates perichondrium
and calcifying cartilage
• Stimulates cells in perichondrium to
differentiate into Osteoblasts
– Becomes periosteum and lays down bone
collar
• Capillaries from nutrient artery grow into
disintegrating cartilage model
– primary ossification centre develops
• Spongy bone forms Trabeculae broken down
and cavity forms5/31/2017 37

38. • Blood vessels penetrate epiphyses
(around time of birth)
• Secondary ossification centres develop
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39. AXIAL SKELETON
• Consist of the skull, vertebral column, ribs and
sternum.
• All these bones constitute the central bony
core; the axis.
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40. The Skull
• Consists of the cranium and the bones of the
face
–The cranium encloses cranial cavity
–Facial bones surround and protect the entrances
to the respiratory and digestive tracts
• Superficial landmarks include the sutures
–Lambdoid
–Coronal
–Sagittal
–Squamous
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41. 5/31/2017 41

42. Skull Bones
• 1 frontal bone
• 2 Parietal bones
• 2 Temporal bones
• 1 Occipital bone
• 1 Sphenoid bone
• 1 Ethmoid bone
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43. • Frontal bone: Bone of the forehead. Forms part of
the orbital cavities and ridges above the eyes. The
coronal suture joins the frontal and parietal bones.
• Parietal bones: Form the sides and roof of the skull.
They articulate at the sagittal suture with each
other, with frontal and occipital bones at coronal
and lambdoidal sutures respectively.
• Temporal bones: Lie on each side of the head and
form fibrous immoveable joints with parietal,
occipital, sphenoid and zygomatic bones.
• Occipital bone: Forms the back of the head and
part of the base of the skull. Form fibrous joints
with parietal, temporal, and sphenoid bones.5/31/2017 43

44. 5/31/2017 44

45. 5/31/2017 45

46. Focus: The Individual Bones of the
Skull Cranial Bones
• one occipital bone
–foramen magnum
• two parietal bones
• one frontal bone
–frontal sinuses
• two temporal
bones
• auditory
ossicles
• one sphenoid
• one ethmoid
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47. 5/31/2017 47

48. 5/31/2017 48

49. Facial bones
• Maxillary bones
• Mandible
• Palatine bones
• Nasal bones
• Vomer
• Inferior nasal
conchae
• Zygomatic bones
• Lacrimal bones
• Hyoid
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50. MAXILLAE
• Largest facial bones
• Form the upper jaw and most of
the hard palate
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51. 5/31/2017 51

52. Palatine and Nasal Bones
• Palatine bones
–Small “L” shaped bones
–Form the posterior hard palate and
floor of the nasal cavity
• Nasal bones
–Superior border of external nares
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53. Vomer, Zygomatic and Lacrimal bones
• Vomer
–Forms the inferior portion of the nasal
septum
• Zygomatic bone
–Temporal process articulates with zygomatic
process of temporal bone
• Lacrimal bones
–Smallest bones of the face
–Sit medially in orbit5/31/2017 53

54. 5/31/2017 54

55. Mandible and Hyoid bones
• Mandible
–Bone of the lower jaw
• Hyoid
–Suspended by stylohyoid ligaments
–Supports the larynx
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56. 5/31/2017 56

57. The orbital and nasal complexes
• Seven bones in the orbital complex
• Nasal complex = bones that enclose
the nasal cavities and paranasal
sinuses
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58. 5/31/2017 58

59. Vertebral column
• Vertebrae, sacrum, coccyx
–7 cervical vertebrae
–12 thoracic vertebrae
–5 lumbar vertebrae
–Sacrum and coccyx are fused
vertebrae
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60. 5/31/2017 60

61. Spinal curvature
• Four spinal curves
–Primary (accommodation) curves =
thoracic and sacral
–Secondary (compensation) curves =
lumbar and cervical
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62. Vertebral anatomy
• Typically has a body and vertebral arch
• Superior and inferior articular processes
• Separated by intervertebral discs
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63. 5/31/2017 63

64. Vertebral regions
• Cervical
–Has distinctive shape
–Large relative size of vertebral
foramen
–Costal processes with transverse
foramina
–Notched spinous processes
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65. 5/31/2017 65

66. Thoracic vertebrae
• Heart-shaped body
• Long slender spinous processes
• Articulations for ribs
• Larger than cervical because it supports
more weight.
• Bodies of transverse process has facets
that articulate with ribs.
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67. 5/31/2017 67

68. 5/31/2017 68

69. Lumbar vertebrae
• Most massive (Largest).
• Least mobile
• Subjected to great stresses
• Have spinous processes for muscle
attachment.
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70. 5/31/2017 70

71. Sacrum
• Made up of Five rudimentary fused
vertebrae which form a triangular bone
• Protects reproductive, digestive and
urinary organs
• Articulates with pelvic girdle and fused
elements of coccyx.
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72. 5/31/2017 72

73. Coccyx
• Consist of four terminal fused vertebrae
which form a very small triangular bone,
the broad base of which articulates with
the sacrum.
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74. Thoracic Skeleton
• The thoracic cage consists of 12 pairs of
ribs, 12 thoracic vertebrae, the costal
cartilages and the sternum.
• Serves for protection & support
• Attachment point for muscles
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75. 5/31/2017 75

76. Thoracic cage
• 1. The ribs are long, thin C-shaped bones.
• The costal cartilages are the flexible structures
by which the ribs are attached to the sternum
• 2. The sternum is a flat bone, shaped
somewhat like a stone arrowhead. It is the
most anterior and medial part of the thoracic
cage.
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77. Sternum
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78. Types of Ribs
• True Ribs (1-7)- connected directly to the
sternum by a strip of costal cartilage.
• False Ribs (8-10)- false ribs connect to the
sternum indirectly
• Floating Ribs (11-12)- do not attach to the
sternum
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79. 5/31/2017 79

80. Features
• Typical ribs- (3-9): head with two articular
facets, neck, tubercle, angle, body & costal
groove
• Atypical ribs- (1& 2, 10-12): head with one
facet
• Intercostal space: space between two ribs
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81. Typical Rib
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82. Atypical Ribs
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83. Rib Articulation
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84. Vertebrocostal Joint
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85. Applied Anatomy
• Rib fractures: anterior to the angle of the
rib
• Dislocated ribs: displacement of a costal
cartilage from the sternum
• Separated ribs: displacement of a rib & its
costal cartilage
• Spina bifida: congenital defect
• Fractures of the Vertebral column
• Herniated disc5/31/2017 85

86. Abnormal Curves of the Vertebral Column
• Scoliosis: Lateral bending
• Kyphosis: an exaggeration of the
thoracic curve
• Lordosis: an exaggeration of the lumbar
curve
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87. LordosisScoliosis
Kyphosis
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88. THE APPENDICULAR SKELETON
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89. Appendicular skeleton consists of the
following;
• Limbs (appendages)
• Pectoral girdle
• Pelvic girdle
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90. The Pectoral (shoulder) girdle
• Composed of two bones
•Clavicle – collarbone
•Scapula – shoulder blade
• These bones allow the upper limb to
have exceptionally free movement
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91. Bones of Shoulder girdle
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92. 5/31/2017 92

93. Bones of the Upper limbs
They include;
• Bone of the arm- Humerus
• Bones of the forearm-
Radius
 Ulna
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94. • The Humerus
Anterior view Posterior view5/31/2017 94

95. • Radius
• Ulna
5/31/2017 95

96. Bones of The hand
•Carpals – wrist
•Metacarpals – palm
•Phalanges – fingers
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97. 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
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98. 5/31/2017 98

99. 5/31/2017 99

100. Bones of
Lower Limbs
• Thigh Bone
Femur
Anterior view Posterior view
5/31/2017 100

101. • Bones of the
Leg
Two bones;
Tibia
Fibula
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102. • The foot
•Tarsus –
ankle
•Metatarsals
– sole
•Phalanges –
toes5/31/2017 102

103. Fractures
• Despite its mineral strength, bone may crack or
even break if subjected to extreme loads, sudden
impacts, or stresses from unusual directions.
– The damage produced constitutes a fracture.
• The proper healing of a fracture depends on
whether or not, the blood supply and cellular
components of the periosteum and endosteum
survive.
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104. 5/31/2017 104

105. Fracture Repair
• Step 1:
A. Immediately after the fracture,
extensive bleeding occurs. Over a
period of several hours, a large blood
clot, or fracture hematoma, develops.
B. Bone cells at the site become deprived
of nutrients and die. The site becomes
swollen, painful, and inflamed.
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106. 5/31/2017 106

107. • Step 2:
A. Granulation tissue is formed as the
hematoma is infiltrated by capillaries and
macrophages, which begin to clean up the
debris.
B. Some fibroblasts produce collagen fibers
that span the break , while others
differentiate into chondroblasts and begin
secreting cartilage matrix.
C. Osteoblasts begin forming spongy bone.
D. This entire structure is known as a
fibrocartilaginous callus and it splints the
broken bone.
5/31/2017 107

108. Types of Fractures
• Fractures are often classified according to the
position of the bone ends after the break:
Open (compound)  bone ends penetrate the
skin.
Closed (simple)  bone ends don’t penetrate the
skin.
Comminuted  bone fragments into 3 or more
pieces. Common in the elderly (brittle bones).
Greenstick bone breaks incompletely. One side
bent, one side broken. Common in children
whose bone contains more collagen and are less
mineralized (lacks sufficient CaPO4).5/31/2017 108

109. Spiral  ragged break caused by excessive
twisting forces. Sports injury/Injury of
abuse.
Impacted  one bone fragment is driven
into the medullary space or spongy bone
of another.
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110. 5/31/2017 110

111. 5/31/2017 111

112. 5/31/2017 112

113. 5/31/2017 113

114. 5/31/2017 114

115. 5/31/2017 115

116. 5/31/2017 116

117. 5/31/2017 117

118. What kind of fracture is
this?
It’s kind of tough to tell, but
this is a _ _ _ _ _ _ fracture.
5/31/2017 118

119. 5/31/2017 119

120. Bone Remodeling
• Bone is a dynamic
tissue.
– What does that
mean?
• Wolff’s law holds
that bone will grow
or remodel in
response to the
forces or demands
placed on it.
Examine this with
the bone on the
left.5/31/2017 120

121. Why may you suspect
someone who has been
a powerlifter for 15
years to have heavy,
massive bones,
especially at the point
of muscle insertion?
Astronauts tend to
experience bone
atrophy after they’re in
space for an extended
period of time. Why?
mechanism of
remodeling on the right!
5/31/2017 121

122. Nutritional Effects on Bone
• Normal bone
growth/maintenance
cannot occur w/o
sufficient dietary intake of
calcium and phosphate
salts.
• Calcium and phosphate
are not absorbed in the
intestine unless the
5/31/2017 122

123. hormone calcitriol is present. Calcitriol
synthesis is dependent on the availability of
the steroid
• cholecalciferol (a.k.a. Vitamin D) which may
be synthesized in the skin or obtained from
the diet.
• Vitamins C, A, K, and B12 are all necessary for
bone growth as well.
5/31/2017 123

124. Hormonal Effects on Bone
• Growth hormone, produced by the pituitary
gland, and Thyroxine, produced by the thyroid
gland, stimulate bone growth.
–GH stimulates protein synthesis and cell growth
throughout the body.
–Thyroxine stimulates cell metabolism and
increases the rate of osteoblasts activity.5/31/2017 124

125. • In proper balance, these hormones maintain
normal activity of the epiphyseal plate (what
would you consider normal activity?) until
roughly the time of puberty.
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126. • At puberty, the rising levels of sex hormones
(estrogens in females and androgens in males)
cause osteoblasts to produce bone faster than the
epiphyseal cartilage can divide. This causes the
characteristic growth spurt as well as the ultimate
closure of the epiphyseal plate.
• Estrogens cause faster closure of the epiphyseal
growth plate than do androgens.
• Estrogen also acts to stimulate osteoblast activity.5/31/2017 126

127. • Other hormones that affect bone growth
include insulin and the glucocorticoids.
–Insulin stimulates bone formation
–Glucocorticoids inhibit osteoclast activity.
• Parathyroid hormone and calcitonin are
2 hormones that antagonistically
maintain blood [Ca2+] at homeostatic
levels.
–Since the skeleton is the body’s major
calcium reservoir, the activity of these 2
hormones affects bone resorption and
deposition.5/31/2017 127

128. Calcitonin
• Released by the C cells of the thyroid gland in
response to high blood [Ca2+].
• Calcitonin acts to “tone down” blood calcium
levels.
• Calcitonin causes decreased osteoclast activity
which results in decreased break down of bone
matrix and decreased calcium being released into
the blood.
• Calcitonin also stimulates osteoblast activity
which means calcium will be taken from the
blood and deposited as bone matrix.
5/31/2017 128

129. Notice the
thyroid follicles
on the right.
The arrow
indicates a C cell
5/31/2017 129

130. Increased blood
calcium
Increased calcitonin
release from thyroid C
cells
Decreased osteoclast
activity
Increase osteoblast activity
Calcitonin Negative Feedback Loop
5/31/2017 130

131. Clinical Conditions
• Osteomalacia
–Literally “soft bones.”
–Includes many disorders in which osteoid
is produced but inadequately
mineralized.
•Causes can include insufficient dietary
calcium
•Insufficient vitamin D fortification or
insufficient exposure to sun light.5/31/2017 131

132. • Rickets
–Children's form of
osteomalacia
–More detrimental due to
the fact that their bones
are still growing.
–Signs include bowed legs,
and deformities of the
pelvis, ribs, and skull.
5/31/2017 132

133. • Osteomyelitis
– Osteo=bone +
myelo=marrow +
itis=inflammation.
– Inflammation of bone
and bone marrow
caused by pus-forming
bacteria that enter the
body via a wound (e.g.,
compound fracture) or
migrate from a nearby
infection.
– Fatal before the advent
of antibiotics.5/31/2017 133

134. • Osteoporosis
–Group of diseases in which bone resorption
occurs at a faster rate than bone deposition.
–Bone mass drops and bones become
increasingly porous.
–Compression fractures of the vertebrae and
fractures of the femur are common.
–Often seen in postmenopausal women because
they experience a rapid decline in estrogen
secretion; estrogen stimulates osteoblast and
inhibits osteoclast activity.
• Based on the above, what preventative
measures might you suggest?
5/31/2017 134

135. 5/31/2017 135

136. References
• Mr. Elad Emmanuel, St Louis UNIHEBS:
Medical Laboratory Scientist- St. Louis Clinic
• Principles of Anatomy and Physiology
• Essentials of Anatomy and Physiology
• Human Physiology- Second ed by Moffett
5/31/2017 136

137. THANKS FOR YOUR
ATTENTION
LECTURE 3: SPINAL COLUMN ANATOMY
5/31/2017 137