Bone reaction to injury Flashcards
What constitutes a bone deformity/anomaly to be genetic?
there are one or more defective genes or variations in expression
What constitutes a bone deformity/anomaly to be acquired?
it occurs in utero, is neonatal, or occurs during juvenile development
What are some types of chondrodysplasia or skeletal dysplasia?
dwarfism, angular deformities, missing part of some limbs, or skull/mandible abnormalities
What is amelia?
when a limb is missing
What is hemimelia?
when limbs are shortened
What is prognathism?
when the mandible is abnormally long
What is brachygnathism?
when the mandible is abnormally short
What is chiari?
when there is an occipital malformation such as an extra hole near the foramen magnum
What can cause chondrodysplasia and skeletal dysplasia?
genetic defects, teratogens, and nutritional abnormalities
What abnormality does veratrum californicum cause?
cyclopia during the 14th day of gestation if the sheep eats it
What abnormality does thalidomide cause?
phocomelia (loss of long bones) in children
What is an example of a nutritional abnormality that leads to chondrodysplasia and skeletal dysplasia?
iodine deficiency that causes goiter in foals and prognathism
What is osteochondrosis?
a focal defect that occurs in endochondrial ossification
If the focal defect in endochondrial ossification is occuring in the AE complex, what type of osteochondrosis is it?
osteochondrosis dissecans
If the focal defect in endochondrial ossification is occuring in the physis, what can happen?
epiphysiolysis - a fracture through the physis because it has become weaker
What animals does osteochondrosis commonly happen to?
animals that are bred for rapid bone growth
What lesions are associated with osteochondrosis?
a plug of necrotic cartilage in the location of osteochondrosis, a defect/flap of articular cartilage, and an uneven joint surface and subchondral bone
What is the mechanism of osteochondrosis dissecans?
- premature vessel closure
- focal AE ischemia
- cartilage necrosis
- focal endochondrial ossification failure with adjacent endochondrial ossification progression
- deformity of articular surface
- necrotic cartilage breaks free into the joint
What is loss of bone characterized as?
net decrease in bone mass
What generally causes loss of bone?
osteoclastic resorption exceeds bone production
What is diffuse loss of bone known as?
osteoporosis or ostopenia
What can cause osteoporosis or ostopenia?
disease, nutritional imbalances, and hyperparathyroidism
What is focal or localized loss of bone known as?
bone lysis
What is bone lysis associated with?
chronic inflamation or neoplasia due to the increase in cytokine production that causes an increase in osteoclastic resorption
What is hyperostosis?
an increase in amount of bone production: woven bone to lamellar bone
What generally causes hyperostosis?
local cytokines recruit and activate osteoblasts to form new bone
What specifically can cause hyperostosis?
compression and periosteal/endosteal injury due to chronic inflammation, neoplasia, trauma/fracture, or it is idiopathic
What is osteosclerosis?
abnormally dense bone - like cortical bone
What is osteosclerosis caused by?
can be caused by the failure of osteoclasis; a decrease in a number and activity of osteoclasts
What is osteopetrosis?
diffuse osteosclerosis of trabecular bone; usually an inherited defect in mammals
What is growth retardation lattice?
metaphyseal osteosclerosis due to the persistence of primary spongiosa
What is osteonecrosis?
death of bone cells
What is osteonecrosis usually caused by?
ischemia, bacterial toxins, heat, and cold
In order for necrotic bone to be removed what must happen?
revascularization is required and osteoclastic resorption must remove the necrotic bone
What is a sequestrum?
a piece of necrotic bone that is walled off and acts as a foreign tissue: occurs when bone is not produced
What can a fracture through the physis lead to?
early closure of growth plate causing shortening because endochondrial ossification does not occur