1. BONE ARCHITECTURE
Dnyanesh Lad

2. • Hardest structures
• Toughness and elasticity
Externally: Pink white
Internally: Red
• On section
(1) Compact tissue-porous
+ dense like ivory
(2) Cancellous tissue

3. MICROSCOPY SUBTYPE FEATURES EXAMPLE
LAMELLAR Cortical
(80%)
Strong; slow
turnover
Along Lines
Of Stress
Femoral
shaft
Cancellous
/ Spongy
>elastic; >
turnover; <
Young’s
modulus
Distal
femoral
epiphysis
WOVEN Immature Non stress
oriented
Embryonic
skeleton
# callus
Pathologic Weak,
Flexible,High
turnover,
Osteosarcoma
Fibrous
dysplasia

5. Periosteum
• Encloses bone
• Supplies blood vessels
• 2 layers (1)Outer-connective tissue+fat
(2)Inner-elastic fibres forming a
dense membranous network
• Medullary membrane/ Internal periosteum

6. Periosteum
In young
• Thick
• Vascular,
• Loosely attached
• Separated by soft
tissue with
osteoblasts
• ossification on
exterior of bone
In adults
• Thin
• Less vascular
• Closely attached
• Osteoblasts
converted to
epitheloid layer.
• Carry lymph from
bone

7. • RAMIFICATION OF VESSELS
• LIABILITY OF BONE
EXFOLIATION OR NECROSIS.

8. BONE MARROW
ADULT
• yellow colour
• Long bones
• Composition:
96% fat
1% areolar tissue +
vessels
3 % fluid
a. fibrous tissue
b. blood vessels
c. cells
CHILD
1. Red colour
2. Short flat bones
3. Composition:
75% water
25% solid matter
a. Cell globulin
b. Nucleoproteid
c. Extractives
d. Salt
e. Less fat

9. • TRUE “MARROW CELLS” OF KOLLIKER
red marrow
Majority of the cells
Roundish nucleated cells
smallest-erythroblasts

11. • GIANT CELLS-MYELOPLAQUES-
OSTEOCLASTS
more in red marrow
large
multinucleated
protoplasmic mass
‘integrin’-attach
TRAP + CA
Fn: absorbtion of bone matrix
Evacuate pits/cavities-”HOWSHIPS
LACUNAE”

12. VESSELS
• Compact bone- more numerous
• Cancellous bone-less numerous
larger size.
Come through compact tissue
• Largest and most numerous apertures
for veins of cancellous tissue.

13. MEDULLARY / NUTRIENT ARTERY
High pressure system
nutrient foramen; shaft
accompanied by 1 or 2 veins
branches in both directions to
medullary membrane
anastamoses with br. Of compact and
cancellous tissue.

14. • METAPHYSEAL/EPIPHYEAL VESSELS
From periarticular vascular plexus-
geniculate arteries
• PERIOSTEAL SYSTEM
Low pressure system

15. • Arterial flow in mature bone is centrifugal
d/t high pressure endosteal system
• In case of displaced fracture flow is
reversed-becomes centripetal.
• Arterial flow in immature bone-centripetal
since periosteum is highly vascularised.

16. VEINS
Emerge from 3 places
1. Accompany artery
2. At the articular extremities.
3. Arising in compact tissue
Venous flow in mature bone-centripetal
Cortical vessels-venous sinusoids-emissary
venous system.

17. LYMPHATICS
1. In periosteum
2. Within bone in Haversian system
NERVES
1. Freely distributed in periosteum
2. Accompany nutrient vessels to interior
3. Most numerous in –articular extremities
vertebrae
larger flat bones

18. MINUTE ANATOMY
Studied on transverse section
Haversian systems
1. Haversian canal
2. Lamallae
3. Lacunae
4. Canaliculi

20. Haversian Canal / Volkmanns Canal
• // to long axis of bone
• Branch + communicate
• Average diameter: 1/500th
of an inch
• Larger near medullary cavity
• Contains- 2 blood vessels
delicate connective tissue
nerve filaments
lymphatics

21. LAMELLAE
Primary / Fundamental / Circumferential
-medullary cavity of bone would be the HC
Secondary / Special
-Those laid down around actual HC
Interstitial
-between the various circular systems, filling the
irregular intervals

22. LACUNAE
branched bone cell / corpuscle
Processes of cell pass through canaliculi
Fn: fluids for nutrition brought in contact
with bone
CANALICULI
Do not communicate with the lacunae of
neighboring HS.

23. CHEMICAL STRUCTURE
• Animal Part / Organic Part: 25%
Bone Cells (4%) Matrix (20%)
• Earthy / Inorganic Part 65%
crystalline hydroxyappetite
amorphous Ca2(PO4)3
Remainder: CaCO3, CaCl2 and MgSO4
Trapped ions: citrate, fluoride, Na K Mg

24. OSSIFICATION
• Intramembranous
skull, maxilla, mandible, clavicle
mesenchymal tissue-scaffold for ossifn
• Intracartilaginous
• Ring of Lacroix-epiphsial ring formed. Does
not further extend to epiphysis
• Zone of Ranvier- ROL + lateral part of
physis + mesenchymal cells

25. Ossification Centres
• Short bones: single point; in the centre
• Long bone: central point for diaphysis (1st
)
1 or more for each extremity-epiphysis
• Union of epiphysis with shaft occurs in
reverse order to that in which ossification
began (exception : fibula)
• Regulated by direction of nutrient artery
(knee-away ; elbow-towards)

26. • When 1 epiphysis; medullary artery is
directed towards it.
• Eg: acromial end of clavicle
distal end of the metacarpal bone of
thumb and great toe
proximal end of other metacarpals
and metatarsals

27. THANK
YOU