necessary info on bone anatomy & fracture healing for post graduate level orthopaedic student

1. ANATOMY
OF
BONE
AND
FRACTURE
HEALING
MODERATOR
:DR.PRAMOD
B
ITAGI
PROFESSOR
&
UNIT
HEAD
DEPARTMENT
OF
ORTHOPAEDICS
PRESENTER
:DR.RAMACHANDRA
Dr.
SREE
KRISHNA
PATURI.

2. ANATOMY
OF
BONE
• INTRODUCTION
• GENERAL
FEATURES
OF
BONE
• CLASSIFICATION
OF
BONE
• MACROSCOPIC
ANATOMY
OF
BONE
• MICROSCOPIC
STRUCTURE
OF
BONE
• COMPOSITION
OF
BONE
• HISTIOGENESIS
OF
BONE

3. INTRODUCTION
• The
basic
unit
of
human
skeleton
is
BONE.
• Human
body
contains
206
bones.
• Bone
is
essenIally
a
highly
vascular,living
constantly
changing
mineralized
connecIve
Issue.
• It
is
remarkable
for
its
hardeness,
resilience
&
regeneraIve
Issue.
• Bone
matrix
composed
of
organic
materials,mainly
collagen
fibres
&
inorganic
salts
rich
in
calcium
&
phosphate.

4. GENERAL
FEATURES
OF
BONE
• Typical
long
bone
has
• DIAPHYSIS
• EPIPHYSIS
• METAPHYSIS

5. DIAPHYSIS:
• The
porIon
of
long
bone
between
two
carIlaginous
ends
is
known
as
DIAPHYSIS.
• It
ossifies
from
primary
centre
of
ossificaIon
which
develops
first
in
early
foetal
life
in
hyaline
carIlage
model
of
future
bone.
• Primary
centre
&
process
of
bone
formaIon
extends
towards
two
ends.

6. EPIPHYSIS:
• The
two
carIlaginous
ends
of
a
growing
long
bone
are
known
as
EPIPHYSIS.
• Epiphyseal
carIlage:It
is
plate-­‐like,thin
layer
of
carIlage
which
seperates
growing
diaphysis
from
epiphysis.
• It
is
responsible
for
growth
in
large
bone.
• The
cells
in
this
conInuously
proliferate
unIl
growth
completed.
• Epiphyseal
line:
The
peripheral
margin
of
epiphyseal
carIlage.

7. METAPHYSIS:
• The
part
of
diaphysis
immediately
adjacent
to
epiphyseal
carIlage
is
known
as
METAPHYSIS.
• It
is
the
site
advancing
ossifcaIon.
Importance:
• Most
vascular
part
of
a
long
bone
because
of
large
anastomosis
of
vessels.
• Growth
acIviIes
are
most
marked
in
this
zone.

8. • It
is
site
of
inserIon
of
muscles,
thus
it
is
liable
to
be
injured
due
to
muscular
strain.
• SomeImes
metaphysis
lies
within
capsular
ligament.So
infecIon
from
diaphysis
may
spread
to
the
joint.

9. PARTS OF BONE

10. CLASSIFICATION
OF
BONE:
• A)According
to
PosiIon:
Axial:Bones
forming
axis
of
body.
Ex:skull,ribs,sternum,vertebrae.
Appendicular
Bones:
forming
skeleton
of
limbs.
• B)According
to
Size&
Shape:
Long
bones:Present
in
upper
&
lower
limbs.
Ex.Femur,radius
Act
as
levers
for
movements
&
locomoIon.

11.
• Short
bones:Polyhedral
&
cuboidal
in
shape.
Ex:Carpal
&
tarsal
bone.
• Flat
bones:Exapanded
&
plate
like.
•
Ex:scapula,sternum,ribs.
• Irregular
bones:Ex:vertebrae
• PneumaIc
bones:Flat
or
irregular
bones
possessing
a
hollow
space
within
their
body
containing
air.
Ex:ethmoid,mastoid
bones....

13. • Sesamoid
bones:They
are
nodules
of
bones
which
develop
in
certain
tendons.
• Do
not
possess
periosteum
&
haversian
system.
• Ossify
aZer
birth.
• Ex:pisiform,patella.
According
to
Gross
structure:
• Compact(Lamellar)bone:
Outer
corIcal
part
of
long
bones,which
is
hard
&
homogeneous
appearence.

14. • Spongy(Cancellous)
bone:The
inner
part
of
long
bones,less
hard
&
presents
a
spongy
appearance.
• Diploic
bone:Consists
of
inner
&
outer
tables
of
compact
bone
&
in
between
a
porous
layer.
Ex:
cranial
bones.
• According
to
Development:
• Memranous
bones.
• CarIlaginous
bones.

16. MACROSCOPIC
ANATOMY
OF
BONE
Living
bone
is
white.
Its
texture
is
either
dense
like
ivory(compact
bone)
or
honeycombed
by
large
caviIes(trabecular,cancellous
or
spongy
),where
bone
elements
reduced
to
a
lacework
of
bars
and
plates.

17. COMPACT
BONE:
• It
is
limited
to
corIces
of
mature
bones(corIcal
bone)
and
is
of
great
importance
in
providing
their
strength
.
• Its
thickness
vary
for
different
bones,according
to
their
overall
shape,posiIon
and
funcIonal
roles.

18. COMPACT BONE

19. CANCELLOUS
BONE
• It
is
usually
internal,
giving
addiIonal
strength
to
corIces
and
supporIng
the
bone
marrow.
• Bone
forms
a
reservoir
of
metabolic
calcium(99%
of
calcium
is
in
the
bony
skeleton)
and
phosphate
which
is
under
hormonal
and
cytokine
control.

20. CANCELLOUS BONECANCELLOUS BONE

21. • In
general
parts
of
bone
terminology:
•
Depression
-­‐
Fossa
•
Lengthy
depression
-­‐
Groove/Sulci
• Notch
-­‐
Incisura
• Actual
gap
-­‐
Hiatus
• Elongated
pointed
projecIon
-­‐
Spine
• Rounded
projecIon
-­‐
Tuberosity/
Trochanter
• Long
projecIons
-­‐
Crests

22. • ProjecIon
close
to
condyle
-­‐
Epicondyle
• Expanded
proximal
ends
-­‐
Head/caput
• Hole
in
bone
-­‐
Foramen
• Plate
of
bone
-­‐
Laminae
• A
large
Laminae
-­‐
Squamae

23. MICROSCOPIC
STRUCTURE
OF
BONE:
• The
basic
structural
unit
of
compact
bone
is
Haversian
system
or
Osteon,named
aZer
Clopton
Havers(1691).
• It
contains
following
structures:
• Haversian
canal
• Lamellae
• Lacunae
• Canaliculi
• Volkamann's
canal

24. Haversian
Canal:
• It
is
present
in
the
centre
of
each
Haversian
system
approximately
20micrometer
in
diameter.
• It
runs
parallel
to
the
long
axis
of
bone.
• Each
canal
consists
of
small
artery,vein,lymphaIcs,thin
fibers
and
supporIng
delicate
areolar
Issue.

25. Lamellae:
• a)Concentric
Lamellae:Thin
plates
of
bony
Issue
consisIng
of
ground
substance
or
matrix
with
collagen
fibres
lying
in
a
calcified
material.
• Arranged
concentrically
around
the
Haversian
canal.
• Adjacent
lamellae
are
held
together
by
interchange
of
fibres.
• b)IntersIIal
Lamellae:Lie
in
the
interval
between
typical
haversian
system.

26. • c)CircumferenIal
Lamellae:Found
at
outer
and
inner
periphery
of
the
cortex.
Lacunae:Small
spaces
between
lamellae,each
containing
a
bone
cell(Osteocyte).
Canaliculi:Are
fine
radiaIng
channels
which
connect
lacunae
with
each
other
and
central
Haversian
canal.
• The
canaliculi
are
occupied
by
proplasmic
processes
of
bone
cells.

28. Volkamann's
Canal:
• Are
oblique
canals
running
at
right
angles
to
the
long
axis
of
bone.
• Contain
the
neurovascular
bundle
and
connect
Haversian
canals
with
the
medullary
cavity
and
surface
of
bone.
• These
canals
are
not
surrounded
by
concentric
lamellae
of
bone.

29. Periosteum:
• As
a
rule
external
surface
of
any
bone
covered
by
a
membrane
called
periosteum.
• Except
that
are
covered
with
ar3cular
car3lage.
• The
periosteum,
consisIng
of
two
layers:
Ø An
outer
FIBROUS
LAYER
and
Ø An
inner
more
cellular
and
vascular
CAMBIUM
LAYER”.

30. • The
thicker,
more
cellular
periosteum
of
infants
and
children
has
a
more
extensive
vascular
supply
than
that
of
adults.
• Perhaps
because
of
these
differences,
the
periosteum
of
children
is
more
acIve
in
healing
many
fractures.
• Young
bones
the
cellular
layer
consists
of
numerous
osteoblast
(osteoprogenIc
layer),
whereas
in
the
adult
osteoblast
are
not
conspicuous,
but
osteoprogenitor
here
can
form
osteoblast
when
need
arises

31. Endosteum:
It
lines
the
walls
of
bone
caviIes
including
the
marrow
spaces
forming
inner
limiIng
membrane.
COMPOSITION
OF
BONE:
a)
Organic
matrix(25%)
b)Inorganic
elements(65%)
c)Water(10%)

32. Organic matrix
bone cells
4%
Intercellular matrix
20%
• Collagens
• Protein peptides
• Proteoglycans
• Lipids
• Osteocyte
• Osteoblast
Bone lining cells
• Osteoclast
Mesenchymal
precursor cells
Osteoprogenator stromal cells

33. Osteoprogenator
stromal
cells:
• From
pleuripotent
stromal
stem
cells
form
bone
marrow
and
connecIve
Issue.
• It
resemble
fibroblast(mesenchlmal
origin)
• DifferenIate
into
osteoblasts.
• Based
on
nature
of
inducIon
these
may
defferenIate
into:
fibroblasts,myoblasts,pericytes,adipocytes,an
d
chondroblasts.

34. Osteoblast:
• 15-­‐30micrometer,basophilic
cuboidal
mononuclear
cells.
• Found
in
surfaces
of
growing
or
remodelling
bone
forming
a
monolayer.
• Responsible
for
synthesis,deposiIon
and
mineralisaIon
of
bone
matrix.
• Its
surface
rich
in
alkaline
phosphatase
acIvity
located
at
plasma
membrane.

35. • It
synthesises:
• Type
1
and
type
5
collagen
• Gamma
carboxylglutamic
acid(GLA)
containing
osteocalcin
and
GIA
protein.
• OsteonecIn
• Proteases
and
growth
factor
• It
bears
receptors
for
Vit.D3,PTH
and
1,25,
(OH)2
VitD3.

36. Osteocyte:
• Major
cell
type
of
mature
bone.
• Derived
from
osteoblasts
which
have
reduced
or
caesed
matrix
formaIon.
• Numerous
fine
process
emerge
from
cell
body
and
interconnect
with
each
other.
• Each
osteocyte
is
in
a
lacunae.
• Average
life
span
25yrs.
• When
dead,they
retract
their
processes
and
becoming
metabolically
inacIve.
• Inhibits
resorpIon
or
addiIon
of
matrix
at
surface.

37. Bone
lining
cells:
• Are
flajened
epithelium
like
cells
parIcularly
evident
in
adult
skeleton
found
on
resIng
surface
of
bone
i,e.those
not
undergoing
deposiIon/
resorpIon.
• It
lines
-­‐Endosteal
surface
of
marrow
cavity
-­‐Periosteal
surface
-­‐vascular
canal
within
osteons.
• Plays
role
in
regulaIng
differenIaIon
of
osteoprogenator
cells.
• Control
ares
of
osteoclasts
on
bone
surface
and
regulate
mineral
homeostasis.

38. Osteoclasts:
• Large
polymorphous
cell
15-­‐20
or
more
nuclei.
• Lie
where
acIve
removal
of
bone
is
occuring
on
surface.
• Responsible
for
removal
of
bone,they
cause
demineralisaIon
by
protein
release
and
also
by
lysosomal
and
non
lysosomal
enzymes.
• Arise
from
mononuclear
lineage.
• Survival
Ime
appr.7wks.
• SImulators
are:PTH,Factors
from
osteoblasts,macrophages/lymphocytes,decreased
intracellular
calcium.

41. Bone
Matrix:
• It
is
the
extracellular
mineralized
material
of
bone
and
consists
of
a
ground
substance
in
which
are
embeded
numerous
collagen
fibres.
• In
early
stages
of
bone
formaIon,before
mineralizaIon,the
matrix
is
Osteiod.
• In
adult
bone
amount
of
osteiod
is
very
small,reflecIng
local
remodelling
of
bone
in
which
mineralizaIon
follows
deposiIon
of
organic
matrix.

42. Collagen:
• Bone
contains
type
1
and
type
5
which
is
thought
to
regulate
fibrillogenesis.
• It
is
synthesized
from
osteoblasts.
• Other
organic
components
of
matrix
like
OsteonecIn
is
phosphorylated
glycoprotein
secreated
by
osteoblasts
and
bound
mainly
to
minerals.
• Osteocalcin
:Glycoprotein
synthesized
by
osteoblasts.it
is
bound
to
mineral
and
is
used
as
a
marker
of
bone
formaIon.

43. Inorganic
elements
Hydroxyapatite
Crystalline Amorphous
Calcium
Phosphate
• Trapped Ions
•
• Citrate
• Fluride
• Sodium
• Magnesium
• Potassium

44. Blood
Supply:
• One
or
two
main
diaphyseal
nutrient
arteries
enter
shaZ
obliquely
through
nutrient
foramina
leading
into
nutrient
canals.
• Entry
is
directed
away
from
dominant
growing
epiphysis.
• Nutrient
arteries
divided
into
ascending
and
descending
branches
in
medullary
cavity.

45. • Near
epiphysis
these
vessels
joined
by
terminals
of
numerous
metaphyseal
and
epiphyseal
arteries.
• Medullary
arteries
of
shaZ
give
of:
• Centripetal
branches
• CorIcal
branches
• Large
irregular
bones
recieve
a
periosteal
supply
and
large
nutrient
arteries
penetraIng
directly
into
cancellous
bone.

47. • Short
bones
recieve
numerous
fine
vessels
from
periosteum
at
non
arIcular
surfaces.
• Arteries
enter
vertebrae
close
to
transverse
processes;their
medulla
drains
to
two
large
basivertebral
veins
converging
to
a
foramen
on
posterior
surface
of
vertebral
body.
• LymphaIc
vessels
accoumpany
periosteal
plexuses.

48. Nerve
Supply:
• These
are
most
numerous
in
arIcular
extremiIes
of
longbones,vertebrae
and
larger
flat
bones.
• Nerves
occur
widely
in
periosteum,
fine
myelinated
and
non-­‐myelinated
fibres
accoumpany
nutrient
vessels
into
bone
marrow
and
lie
in
perivascular
spaces
of
Haversian
canals.

49. HISTIOGENESIS
OF
BONE:
• Bone
first
appears
aZer
7th
embryonic
week.
• They
develop
from
embyonic
mesenchymal
Issue.
• The
process
of
gradual
bone
formaIon
is
called
OssificaIon.
• These
are
of
two
types:
• 1)Endochondral
OssificaIon
• 2)Membranous
OssificaIon

50. • 1)Endochondral
OssificaIon:
• In
embryonic
life
most
of
skeleton
is
composed
of
carIlage,
which
is
absorbed
&
replaced
by
bone.
• This
process
known
as
Endochondral
OssificaIon.
• It
begins
prenatally
&
conInous
throughout
postnatal
period
unIl
growth
is
complete.

51. • 2)Membranous
OssificaIon:
• When
bone
is
formed
directly
from
a
loose
form
of
connecIve
Issue
without
intervening
stages
of
carIlage
formaIon,
calcificaIon
and
resorpIon
and
process
is
known
as
Membranous
OssificaIon.

52. Mesenchyme to bone

55. MICROSCOPIC
ORGANIZATION
OF
BONE
Woven
Bone
• Immature
bone
• Forms
De
novo,
Healing
bone
• Rate
of
deposiIon
&
turnover
is
Rapid.
• Collagen
fibrils:
Irregular
Diameter
&
no
consistent
orientaIon.
• Lamellar
Bone
• Mature
bone
• Forms
only
in
exisIng
bone.
• It
is
Slower.
• Regular
&fibrils
organized
in
response
to
loads.

56. • Woven
Bone
• Osteocytes:
• variable
in
size,
mineral
density
&
orientaIon
&
numerous
in
number.
• It
is
easily
deformed.
• Lamellar
Bone
• Osteocytes:
• Regular&
lie
between
lamellae
&
mineral
density.
• It
is
sIffer.

57. FRACTURE
HEALING
• HISTORY
• INTRODUCTION
• STAGES
OF
FRACTURE
HEALING
• VARIABLES
INFLUENCE
IN
#
HEALING

58. HISTORY:
• Bones
have
broken
since
begining
of
humanity
and
have
been
recognised
as
long
as
recorded
history.
• John
Hunter,a
pupil
of
Haller
described
morphologic
sequence
of
fracture
healing.
• In
1917,Bier
reported
sImulaIon
factor
for
new
bone
formaIon
was
present
in
organized
blood
clot
of
the
fracture
haematoma.

59. INTRODUCTION:
• A
fracture
is
defined
as
a
break
in
conInuity
of
bone.
• Fracture
in
man
heal
and
unite
by
two
main
ways:
• 1)Primary/Osteonal/Direct
Healing:
•
Bone
formaIon
occurs
directly
without
any
callus
formaIon.This
occurs
parIcularly
in
stable,aligned,closely
apposed
fracture.

60. 2)Secondary/Indirect
Healing:
• It
is
usual
type
consisIng
of
formaIon
of
callus
either
of
carIlaginous
or
fibrous.
• This
callus
is
later
converted
into
lamellar
bone.
• When
fracture
is
not
rigidly
fixed
and
movements
occur,in
such
cases
callus
is
replaced
by
bone
healing.
• On
x
ray
charecterised
by
abundant
callus
formaIon,temporary
widening
of
fracture
gap
and
slow
disappearance
of
radiolucent
fracture
line
due
to
fibrocarIlage
mineralisaIon.

61. STAGES
OF
FRACTURE
HEALING:
• OsteoinducIon
is
a
first
step
in
bone
healing.
• It
causes
mesenchymal
cells
to
differenIate
into
various
cells
which
then
proliferate
&
produce
messenger
substances
which
further
sImulate
mesenchymal
cells
to
differenIate.
• OsteconducIon
a
scaffold
of
collagenous
network
has
developed
upon
which
reparaIve
cells
produce
callus
&
bone.

62. The
various
stages
of
#
Healing
includes:
• Stage
of
Haematoma
FormaIon.
• Stage
of
GranulaIon
Issue.
• Stage
of
Repair/Callus.
• Stage
of
ConsolidaIon.
• Stage
of
Remodelling.

63. Stage
of
Haematoma
FormaTon:
• Begins
immediately
following
injury
and
followed
rapidly
by
repair.
• The
Haematoma
provides
3
imp.
factors:
• It
immobilizes
#
and
swellings
hydrostaIcally
splints
the
#
and
thus
provides
small
amount
of
mechanically
stability
of
#
site.

64. • It
provides
a
fibrin
scaffold
that
facilitates
migraIon
of
repair
cells.
• Haematoma
brings
the
osteclast
&
chondrocyte
precursors
to
#
site
in
large
numbers
that
begin
to
differenIate
into
osteoblasts
and
chondrocytes
to
begin
producing
matrix.
• The
loss
of
haematoma
will
impair
the
#
healing.

66. Stage
of
GranulaTon
Tssue:
• GranulaIon
Issue
replaces
iniIal
haematoma
&
differenIates
into
connecIve
Issue
&
fibrocarIlage.
Injured
Issue
&
platelets
Vasoactive meditors
New vessels,fibroblasts,
intercellular matrix
Granulation
tissue

67. Stage
of
Repair/Callus:
Osteogenesis
Cartilage cells lay in osteoid tissue
Matrix with type 1 collagen fibrils
Deposition of calcium Hydroxyappetite
Callus / Woven/Immature bone

68. Stage
of
ConsolidaTon:
• By
the
acIvityof
osteoblasts
woven
bone
transformed
into
mature
bone.
Stage
of
Remodelling:
• The
process
occurs
along
with
deposiIon-­‐
resorpIon
phenomenon.
• osteoclast
has
important
role
in
this
phase.

69. Remodelling
does
four
things:
• It
replaces
mineralised
carIlage
with
woven
bone.
• Packets
of
new
lamellar
bone.
• New
secondary
Osteons
made
of
Lamellar
bone.
• It
tends
to
remove
any
callus
plugging
marrow
cavity

71. FRACTURE
HEALING
IN
CANCELLOUS
BONE:
• The
extent
of
bone
&
marrow
necrosis
following
cancellous
bone
#
is
much
less
than
in
compact
bone,because
of
good
circulaIon.
• Primary
healing
takes
place
in
this,secondary
healing
is
rare
and
endochondral
bone
formaIon
excepIonal.

72. VARIABLES
INFLUENCE
IN
#
HEALING:
• Cruses
and
Buck
Walter
have
divided
variarles
into
four
groups
1)INJURY
VARIABLES:
Ø Open
Fractures:Delays
repair
by
soZ
Issue
disrupIon
&disturbed
blood
supply
to
#
site.
Ø severity
of
injury:Extensive
soZ
Issue
&
•
bone
damage
leads
to
delayed
#
healing.

73. Ø IntraarTcular
fracture:
It
requires
reconstrucIon
of
joint
surface,stable
fixaIon
&
early
mobilisaIon.
Ø Segmental
fracture:It
leads
to
delayed
union/
non
union
due
to
disrupted
intramedullary
blood
supply
of
middle
fragments.
Ø SoX
Tssue
interposiTon:Open
reducIon
to
extricate
interposed
Issue
will
enhance
#
healing
process.
Ø Damage
to
blood
supply:Delay
#
healing.

74. 2)PATIENT
VARIABLES:
Ø Age:Extremes
of
age
have
influenes
on
#
healing.
Ø Nutri3on:Poor
nutriIonal
status
affects
#
healing
&
can
lead
to
mortality
&
surgical
complicaIons.
Ø Systemic
Hormones:
Steroids,anIcoagulants,anIinflammatory
drugs
inhibit
whereas
GH,insulin
thyroid
hormone
enhance
#
healing.
Ø Nico3ne

75. 3)TISSUE
VARIABLES:
Ø Form
of
bone:Cancellous
bone
healing
is
rapid
due
to
larger
surface,rich
in
cells
&
blood
supply.
Ø Bone
Necrosis
Ø Bone
diseases:Osteoporosis,Primary
malignant
bone
tumours,metastasis,bone
cysts
etc...
all
cause
pathological
bone
#
and
delay
bone
healing.
Ø Infec3on:It
slows
down/prevents
healing.

76. 4)TREATMENT
VARIABLES:
Ø Apposi3on
of
#
Fragments:Decreasing
#
gap
decreases
volume
of
repair
Issue
needed
to
heal
#.
Ø Loading
&
Micrimo3on:Loading
a
#
site
&
induced
micrimoIon
along
bone
#
sites
promotes
healing
but
too
much
moIon
lead
to
non
union.
Ø Fracture
Stabilisa3on:It
will
prevents
repeated
disrupIon
of
repair
&
enhances
#
callus.

77. Ø Rigid
Fixa3on:Stable
fixaIon
allows
early
mobilisaIon
of
joints
&
hence
prevents
sIffness.
Ø Bone
GraIing:It
is
osteoinducIve
&
osteoconducIve.
Ø Demineralised
Bone
marrow:The
factors
in
bone
marrow
sImulate
bone
formaIon,by
migraIon
of
undifferenIed
mesenchymal
cells
to
implanted
matrix
&
differenIaIon
into
mesenchymal
cells.

78.
DHANYAVAAD