Updated: 10/10/2016

Bone Circulation

Topic
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Questions
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Introduction
  • Bone receives 5-10% of cardiac output
  • Bones that receive tenuous blood supply
    • scaphoid
    • talus
    • femoral head
    • odontoid
  • Blood supply to long bone comes from three sources  
    • nutrient artery system
    • metaphyseal-epiphyseal system
    • periosteal system
Nutrient Artery System
  • High pressure system that branches from major systemic arteries
  • Enter the cortex through the nutrient foramen and enter the medullary canal
    • then branch into ascending and descending branches
      • then branch into arterioles and supply the inner 2/3 of mature bone via the haversion system 
Metaphyseal epiphyseal system
  • Arteries arise from periarticular vascular plexus
    • e.g. geniculate arteries
Periosteal System
  • Low pressure system that supplies the outer 1/3 of bone
    • connected by
      • Volkman's artery (perpendicular to long axis)
      • Haversion system (parallel to long axis)
Intracortical Vascularization
  • Intracortical vessels travel within canals
    • Primary Haversian canals
    • Secondary Volkmann canals
Direction of Arterial Flow
  • Normal intraosseous blood flow rate is 5-20ml/min/100g of bone 
  • Mature bone
    • flow is centrifugal (inside to outside)
      • because of high pressure nutrient artery system and low pressure periosteal system
  • Immature bone
    • flow is centripetal (outside to inside)
      • because low pressure periosteal system predominates
  • Factors increasing blood flow
    • hypoxia
    • hypercapnia
    • sympathectomy
Direction of Venous Flow
  •  Mature bone  
    • flow is centripetal (outside to inside)
      • cortical capillaries drain to venous sinusoids, which drain to the emissary venous system
Growth Plate
  • Perichondrial artery is the major source of nutrition of the growth plate 
Pathoanatomy
  • Fractures
    • patterns of blood flow following fracture
      • immediate phase
        • initial decrease in blood flow after fracture
        • flow is centripetal (outside to inside)
          • because high pressure nutrient artery system is disrupted
          • low pressure periosteal system predominates
    • hours to days
      • increase in blood flow (regional acceleratory phenomenon)
      • peaks at 2 weeks and returns to normal in 3-5 months
  • Intramedullary nails
    • 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
    • tight fitting nails compromise cortical perfusion and reperfusion is slow
 

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Questions (2)

(OBQ12.157) Which of the following arteries provides the blood supply to the outer third of a long bone diaphysis? Review Topic

QID: 4517
1

Nutrient artery

14%

(515/3636)

2

Periosteal arterioles

82%

(2979/3636)

3

Medullary artery

1%

(42/3636)

4

Emissary artery

1%

(23/3636)

5

Perichondral artery of LaCroix

2%

(58/3636)

ML 2

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

(OBQ05.107) Disruption of which of the following interrupts the major source of nutrients to the growth plate? Review Topic

QID: 993
1

Diaphyseal artery

2%

(21/1036)

2

Metaphyseal artery

31%

(324/1036)

3

Perichondrial artery

65%

(670/1036)

4

Synovial fluid

1%

(14/1036)

5

Synovial blood vessels

0%

(2/1036)

ML 3

Select Answer to see Preferred Response

PREFERRED RESPONSE 3
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Topic COMMENTS (3)
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