Definition
Functions
Classification
Composition of bone
Macroscopic structure of bone
Parts of developing bone
Structural elucidation
Blood supply of bone
Ossification
Growth at epiphysial plate
Bone remodeling
Fracture healing
Physiological aspects
Applied anatomy
Bone is a dynamic, highly vascular specialized
connective tissue, which supports the body and provides
leverage for movements.
Protection
Shape
Movement
Hematopoiesis
Mineral storage
Provide surface area for attchment of muscles, tendons,
ligaments.
ACCORDING TO
Shape
Development
Position
Structure
 Long bone Ex:Humerus
 Short bone Ex: Carpal and tarsal





bones
Flat bones. Ex: Ribs, sternum,
scapula
Irregular bones
Ex: Vertebra and hip
bones
Pneumatic bones
Ex: Maxilla, sphenoid,
ethmoid bones
Seasamoid bones
Ex: Patella, fabella,
pisiform
Accessory bones
Ex: Sutural bones.
Membranous bone. Ex: Bones of vault of
skull, facial bone.
Cartilaginous bones. Ex: Bones of limbs and
vertebral column.
Axial skeleton. Ex: Skull. Thoracic cage, vertebral
column.
Appendicular skeleton. Ex: Bones of limbs.
For decalcified bone:
Fixation
Decalcification
Processing
Cutting
Staining
'Dehydration
Clearing
Impregnation
Embedding
For undecalcified bone:
Rub the bone over stone till it becomes transparent.
Matrix
Cells
Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts
Bone lining cells
Organic
Inorganic
Collagen
Non
collagen
Calcium
Phosphorous
Stem cells of
mesenchymal origin.
Proliferate and
convert themselves
into osteoblasts.
Rounded or oval in
Nucleus
Cytoplasm
shape.
Basophilic cytoplasm.
Eccentrically placed
ovoid, euchromatic
nucleus.
Diagrammatic representation
Synthesis and secretion of organic matrix.
Calcification of bone matrix.
Hormonal regulation of bone resorption.
Derived from osteoblasts.
Present in lacunae.
Less basophilic
cytoplasm.
Functions:
Play a role in removal or
deposition of matrix and
Ca when required.
Large polymorphic
cells.
Howship’s lacunae.
Acidophilic
cytoplasm.
Ruffled border.
Clear zone.
Basal zone
It belongs to mono
nuclear phagocytic
system.
Nucleus
Basal zone
Clear zone
Local removal of bone during bone growth.
Remodeling of osteons.
It secretes acid phosphatase, collagenase and
other proteolytic enzymes.
Flattened cells.
Present on bone
surface where active
bone deposition or
resorption take place.
Glycosaminoglycans
Proteoglycan
Water
Organic
Inorganic components
Collagen
•Type 1
Non collagen
•Osteocalcin
•Osteonectin
•Osteoprotogrein
•Bone proteoglycan
biglycan
Major
components
Calcium
Phosphate
Hydroxyl
Carbonate
Minor
components
Magnesium
Sodium
Potassium
Fluoride
Chloride
Iron
Copper
Aluminum
Citrate
Shaft
Periosteum
Outer fibrous
Inner cellular
Cortex
Compact bone
Medullary cavity:
Red or yellow bone
marrow.
2 Ends:
Covered by hyaline cartilage.
 Epiphysis
Types
Traction epiphysis
Pressure
Atavistic
Aberrant
 Epiphyseal plate of cartilage
 Diaphysis
 Metaphysis
Haversian system
 Structural unit
 Haversian canal
 Lacunae
 Mineralised matrix in
lamellae.
 Canaliculi
 Volkman’s canal
 Cement line
Interstitial lamelle
Concentric lamellae
 Circumferential
lamellae
 Meshwork of
trabeculae.
Nutrient artery
Epiphysial artery
Metaphysial artery
Periosteal artery
Intramembranous ossification.
Endochondral ossification
Mesenchymal cells
differentiate into
osteoblasts
Centre of ossification
Osteoblast secrete
organic inter cellular
substance.
Some cells surrounded by
matrix forming lacunae.
Osteoblast to Osteocytes.
Osteoblast secrete
alkaline phosphatase
which calcifie the matrix
Ossification centre grows
radially forming trabeculae
Cancellous bone
Compact bone
1.
Zone of reserve cells
2.
Zone of proliferation
3.
Zone of hypertrophy
4.
Zone of calcification
5.
Zone of ossification
Depends upon the balance of resorption and
deposition of bone.
Two processes:
Appositional growth.
Resorption of bone surface.
Factors:
Strain
Stress
Body movements
Pregnancy
Hematoma formation.
Fibrocartilaginous callus
formation.
Bony callus formation.
Bone remodelling.
HORMONAL EFFECTS
Parathyroid hormone
↑ bone resorption.
↑number and activity of osteoclasts.
↑absorption of calcium from gut.
Calcitonin
↑bone formation & osteoblast activity.
↓osteoclast activity
↓absorption of calcium in gut.
Growth hormone
Act on epiphysial plate.
Regulator of height.
Estrogen
↑Bone formation.
Testosterone
↑Bone mass and strength.
Vitamin A: Regulate the activity, distribution and
co-ordination of osteoblast and osteoclast.
Vitamin C: Act as coenzyme in collagen synthesis
Vitamin D: Calcification of bone matrix.
OSTEOPOROSIS
Bone becomes brittle
and increased risk of
fracture.
Vitamin D deficiency.
Softening of bone.
 Uncontrolled
osteoclastic erosion
followed by osteoblastic
activity.
 Bone becomes weak.
 Compact bone is
converted into lamellar
bone.
Osteoid osteoma
Osteosarcoma
Osteochondroma
Chondrosarcoma
 Benign tumours arise
from osteoblasts.
 Small nidus of osteoid
and woven bone with
inter connected
trabeculae.
 Primary malignant
tumour of bone.
 Pink stained osteoid.
 Pleomorphic tumour
cells derived from
osteoblast with much
mitotic activity.
 Malignant cartilaginous
tumour arises usually in
axial skeleton.
 Tumour shows nodules
of pale hyaline matrix
with chondrocytes.
 Benign tumour usually
occur at the ends of long
bone.
 It consists of both
cartilage and bone.
 Gray’s Anatomy, 40th edition, Susan Standring
 Histology, 8th edition, Ham .A.W.,
 Histology- A Text and Atlas, 5th edition, Ross.M.H.,
 Basic Histology, 11th edition, Junqueoria .L.C.,
 Wheater’s- Functional Histology, 5th edition, Barbara
Young
 Robbins Basic Pathology, 8th edition, Kumar.V.,