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19 Cards in this Set
- Front
- Back
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how much blood circulation does the bone have?
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10 mL/min per 100g wet bone
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what happens in bone when systemic BP rises? with EPI? whats the highest pressure part?
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- riske in pulse pressure
- decrease in pulse pressure from constriction of the nutrient artery - d>m>e |
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4 sources of blood for the bone
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- nutrient artery
- periosteal - small that enter met - small that enter ep |
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perostial vessels supply what? nutruent artery?
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- outer 1/3 of cortes
- inner 2/3 and haversian systems |
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what bloody supply goes thrgouth metaphyseal channes
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- some vesses that enter marrow cavity to anasatomose w/ nutrient artery
- mainly veins to let blood leave marrow cavity |
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what bloody supply goes through epiphyseal channels
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- passage of vessels to 2o oss centers
- isolated in child, join w/ met vessels in closure |
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why does bone necrosis look more dense?
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- osteoclastic resorption + new bone formation
- compression of bone |
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what happes w/ loss of circulation of the terminal vessels in the nutrient artery in kids?
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- interferes w/ enchondral oss
- new cartilage keeps forming, but it isn't ossified until circuation is restored - this is usually really fast in kids |
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can adults have cortical bone death?
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- no
- lots of ep-met collateral circulation - makes an ASx infarct that heal by calcification |
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what does it mean if adults have pain w/ a met infarct?
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- they can't necrose cortical bone
- so it means emboli of nutrient artery - caisson disease (the bends) w/ nitrogen bubbels entraped - this shouldn't impair function that much |
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Perthes disease
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- osteochondrosis of the femoral head
- males 5-10 - long growth ceases, and if there isn't quick restoration of blood supply, the physis closes |
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Kohler disease
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- osteochondrosis of the talar navicular
- long growth ceases, and if there isn't quick restoration of blood supply, the physis closes |
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Frieburg disease
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- osteochondrosis of the 2nd metatarsal head
- long growth ceases, and if there isn't quick restoration of blood supply, the physis closes |
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where are adults at risk of osteonecrosis?
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- femoral head
- talus (body w/ neck is fractured) - lunate - scaphoid (proximal) |
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tx of perthes disease
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- protect it from localized stress by maintaining complete coverage of the head by the acetabulum
- keep it abducted and internally rotated - takes 2-3 years |
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etiology of adult femoral head AVN
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- aterial compromise (fracture of neck, arterial thrombosis from Sickle cell)
- high intraosseius P (steroids, alcohol, Gaucher glycogen storage disease) from increased marrow cellularity and fat |
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tx of adult femoral head AVN
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- early intraosseous P, you can drill the head
- later, bone grafting - after collapse, osteotomy - even later, replacement |
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whats the deal with increased bone blood circulation in children?
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- from fracture, infection, AV fistulae
- can cause overgrowth |
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whats the deal with increased bone blood circulation in adults?
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- degenerative arthritis
- Pagets (can even compromise CO) |
