Blood supply of Bones

1. BLOOD SUPPLY OF BONES
Dr Thouseef A Majeed
MS Ortho PG
VMKVMCH
Salem

2. Types of bones

3. Anatomy of a long bone
Copyright 2009 John Wiley & Sons, Inc.

4. Bone tissue cell types
• Osteogenic cells – unspecialized stem cells
• Osteoblasts – bone builders
• Osteocytes – mature bone cells derived from
osteoblasts
• Osteoclasts – bone ‘breakers’ are multinucleate

6. • Bone receives 5-10% of cardiac output
• Bones that receive tenous blood supply
– scaphoid
– talus
– femoral head
– odontoid

7. Blood supply to long bone comes from three
sources
– Nutrient artery system
– Metaphyseal and epiphyseal system
– Periosteal system

8. Copyright 2009 John Wiley & Sons, Inc.

9. Nutrient foramen
• Oblique canal situated in the
diaphysis of long bones.
• Nutrient canals slope away from
the knee for femur tibia and fibula.
• Canal facing towards elbow in
radius, ulna, and humerus
• 90% of long bones have single
nutrient foramen in middle third of
the shaft

10. Nutrient artery system
• All long bones have one or more nutrient
arterites that enter through a nutrient
foramen
• High pressure system that branches from
major systemic arteries
• Enter the cortex through the nutrient foramen
and enter the medullary canal
– Then branches into ascending and
descending branches
– Each branch sends lateral oriented
arteriolar branches
– Ascending and descending branches
travels to the end of the bone they
anastomosis with metaphyseal and
epiphyseal vessels

11. • With in the cortex they give rise to branches ,
Some extending longitudinally along the axis of
long bone while others proceed radially and
ultimately forms capillaries with in the haversion
system .
• Some arterioles transfers the entire cortex to
reach and anastomose with periosteal arteriolar
network.
• With in the marrow , Some arterioles are short and
profusely branched to supply the capillaries for
the marrow .
• This system supplies the inner 2/3 of mature bone
via the haversion system.

12. Metaphyseal system
• Derived from the neighboring
systemic vessels.
• These arteries directly go into
the metaphyses and reinforce
the metaphyseal branches of
the primary nutrient artery.

13. Layers of Epiphysis

14. Epiphyseal arteries
• The epiphysis has openings that permit
passage of large number of vessels into
and out of the ossification centers.
• Growth plate itself is avascular & receives
nutrition from 2 sources.
• Epiphyseal vessels that supply resting,
germinal, proliferating, and
upper hypertrophic cell layers by diffusion
• Metaphyseal vessels that supply zone of
provisional calcification.

15. • In young child, epiphyseal vessels are
separated from metaphyseal vessels.
• Following growth arrest of the cartilage plate,
there is an anastomoses between epiphyseal
vessels, metaphyseal vessels, & terminal
branches of nutrient artery.
• Obliteration of epiphyseal blood supply results
in necrosis of epiphysis & deprives deeper
cartilage cells of growth plate for their
nutrition.

16. • Longitudinal growth ceases &collateral
circulation is not quickly restored,
permanent closure of epiphyseal plate
occurs.
• Epiphyseal vessels are responsible for
permitting longitudinal growth to occur.
• Metaphyseal vessels
nourish osteoprogenitor cells , which lay
down bone on cartilage matrix.

17. Anatomy of periosteum
• Periosteum consists of two
layers outer fibrous and
inner cambium layer.
• The fibrous layer contains
fibroblasts
• The cambium layer
contains progenitor cells
that develop into
osteoblasts.

18. Periosteal System
• Low pressure system that supplies
the outer 1/3 of bone
• Forms an extensive network of
vessels covers entire length of the
bone shaft.
• Periosteal vessels send small
branches through minute channels
in cortex to supply about outer 1/3
of cortex.

19. • Periosteal arteries are the arteries
of periosteum being especially
numerous beneath the muscular
and ligamentous attachment.
• Beneath the periosteum they
divide into branches and thereby
entering the Volkmann’s canals to
supply the outer one third (1/3)
portion of the cortex.

20. Paediatric Blood supply
• Circulation in pediatric bone differs
from adult circulation due to
requirements of growth & presence of
epiphyseal plate.
• Terminal branches of nutrient artery,
along with metaphyseal vessels,
approach growth plate in a parallel
relationship.
• Branches are so numerous as they
reach growth plate that there is almost
one vessel for each column of cartilage
cells.

21. • In final few mm before terminal
arteriole reaches cartilage, it is
encased in a tube of enchondral
bone
• Children, while periosteum is
actively engaged in circumferential
bone growth, blood supply in this
area is much more abundant than it
is in adult

22. Venous drainage of bone
• Long bones posses a large venous sinus
• Long bones drains into central venous sinus
,from Central venous sinus through nutrient
vein, periosteal veins and emissery veins it
drains out
• Metaphyseal/epiphyseal veins – drain blood
from the proximal and distal regions of the
medullary cavity
• Periosteal veins – drain blood from the ends
of long bones and the red bone marrow

23. Physiology of blood flow
• 5-20ml/min in 100gm of wet bone tissue
• 4-10% of resting cardiac output
• Metaphysis has highest blood flow stimulating factors
– sympathetic nerves
– acid metabolites
– increased or decreased CO2 tension

24. Blood Flow throug the bone
• The direction and extent of blood flow with
in the diaphyseal cortex remains
controversial
• There are two theories behind this
Centrifugal flow and centripetal flow
Centrifugal flow
• With the blood entering the endosteal
aspect from the medullary nutrient system
and flowing through the periosteal surface
.

25. Centripetal flow
• The medullary nutrient system is
interpted ,the periosteal system
provides a reverse supply and blood
flow becomes centripetal (Towards the
center)

26. Periosteal flow
• The role of periosteal vessels has not
been clearly defined.
• Periosteal system originates mainly from
the surrounding muscles and provide
the blood supply to the outer one third
to one half of cortex .
• At the outer aspect of the cortex many
thin walled vessels with in the haversian
canal are observed to be in continuity
with arterioles with in the periosteum.

27. Metaphysal and Epiphysal flow
• The end of the long bones are supplied by
vessels that enter the metaphysis and epiphysis
through small foramina at the periphery.
• After entering the bone these arterioles branch
into arterial arcades, forming a dense
interlocking network
• The vessels becoming progressively smaller in
caliber as they approach subchondral zone
• In subchondral zone they terminate as small
capillary loops

28. Variations In Cortical Blood Flow
• In a normal extremities, not all blood vessels are functional at
the same time. Blood transport occurs through a limited number
of vessels, the other being considered in a resting state
• Under certain conditions(fracture of opposite extremities) a
grater number of blood vessels become actively functional and
demonstrate by micro angiographic methods.

29. Impairment of diaphyseal blood supply
• If the circulation in bone marrow and periosteum is interrupted , an
increase in metaphyseal blood flow occurs
• If circulation through nutrient arteries and metaphyseal vessels are
interrupted, proliferation of periosteal vessels and increased periosteal
blood flow takes place(often accompanied by periosteal newborn
formation)
• When the blood flow through the nutrient artery is interrupted,
approximately 2/3rd of the cortex becomes ischeamic and necrotic, outer
third remains viable .

30. Reversal of venous blood flow
• Under certain circumstances blood flow through large peripheral
veins can be reversed into alternative routes with in the
medullary cavity
• When there is interferance with venous return through main
veins of extremities , the medullary pressures with in the regional
long bones are increased .so collateral venous return takes place
through medullary venous channels.

31. Blood supply of head and neck of femur

32. Blood supply of scaphoid

33. Blood supply of talus

34. Applied aspects
Periosteal stripping
• If the periosteum is stripped and left detached from the cortex and
nutrient artery is preserved, only outer third of the cortex become
ischeamic and necrotic ( often followed the development of
periosteal newborn formation)

35. Intra medullary nail
• Unreamed intramedullary nails preserve endosteal
blood supply
• Reaming devascularizes inner 50-80% of the cortex and
delays revascularization of endosteal blood supply.
• Loose fitting nails spare cortical perfusion and allow
more rapid reperfusion

36. • Tight fitting nails compromise cortical perfusion and reperfusion is
slow
• If the nutrient artery is supressed (intra medullary nailing)
compensatory periosteal vascular proliferation occurs and the
viability of cortex to a great extent .
• When the medullary nutrient blood supply is interepted + stripping
of periosteum = entire thickness of cortex becomes necrotic

37. Nonunion
1. scaphoid fracture
2. neck of femur fracture
3. Talus fracture
Distal tibial fractures
Should be fixed due to
 the nutrient artery divides into three ascending branches & a single
descending branch.
 Bulk of muscle is more over proximal tibia than distal tibia

38. Osteomyelitis
 Hair pin arrangements of arterioles
 Sluggish flow
 Tortous blood vessels and skimming of bacteria

39. References
• Turek
• Apleys
• Inderbir Singh text book of histology

40. THANK
YOU