Bone Path 2 Flashcards
Amelia
Congenital abnormalities in utero, fetus lacks limbs
Polydactyl
More than normal digits
Osteopetrosis pathogenesis
Inherited defect in osteoclastic reabsorption
Increased thickness of bone (osteoscleriosis) bones become brittle and prone to fracture
Osteopetrosis is common in what species
Cattle, sheep, dogs, horses, rats, mice
Common initiation - BVD, FeLV, ALV
Craniomandibular osteopathy
Lion jaw - proliferation of mandible
<1 year, can regress if treated
Common in terriers (autosomal rec) Irish setters
Pathogenesis of craniomandibular osteopathy
Bilateral, symmetric thickening on mandible, occipital, temporal bones
Tympanic bullae
Chondrodysplasia
Or chondrodystrophy
Inherited defect of growth plate cartilage (physis & articular epiphyseal cartilage complex)
Premature growth plate closure, shortens long bones but normal width
Chondrodysplastic dwarfs
Common in dachshund, Pekingese, Bassett hound (selective breeding)
Different types of chondrodysplasia in cattle, sheep & dogs
Why is width normal in long bones w chondrodysplastic dwarfs?
Width is due to growth in intramembranal ossification
Length growth is due to growth plates in bone
Spider lamb chondrodysplasia
Too much gas, excess proliferation of articular cartilage
Osteochondrosis
Failure or delay of endochondral ossification
Metaphysical growth plate, epiphyseal cartilage (AECC)
Mechanisms of osetochondrosis
Multi factorial - very complex
Genetics, rapid growth, vascular factors!! Traumatic injury
Common in pigs bc the breed has been selected to grow very fast
Lesions of osteochondrosis
Retention of cartilage - failure of mineralization, invaded blood vessels
ODC - osteochondrosis dissecans
Articular cartilage flap forms secondary to osteochondrosis at the articular epiphysis
Stages of osteochondrosis
Latens
Manifesta
Dissecans
Pathogen of osteochondrosis latens
Areas of ischemic cartilage present in AC
Pathogens of OC manifesta
Visible lesion in zone of mineralization
Pathogens of OC dissecans
Flap of cartilage is cut off from synovial fluid and dies, falling off bone /AC
Wobblers syndrome
Cervical vertebral stenotic myelopathy
Cervical vertebral stenotic myelopathy
Common in horses & dogs - presents differently
Due to abnormal development of cervical vertebra
Static cervical vertebral stenotic myelopathy
Compression of spinal cord 24/7
Discs C5-6, 6-7
Dynamic cervical vertebral stenotic myelopathy
Compression can change during flexion/extension
Discs C3-4, 4-5
Associated w osteochondrosis of the cervical facets
(Facet = articulating portion of vert bodies)
Developmental abnormalities in bones
Osteopetrosis
Craniomandibular osteopathy
Chondrodysplasia
Osteochondrosis
Cervical vertebral stenotic myelopathy
Metabolic bone diseases
Osteoporosis
Osteopenia
Fibrous osteodystrophy
Osteoporosis
Reduction in bone density = easily fractured
Osteopenia
Reduction in bone mass with no clinical disease
Causes of osteoporosis
Malnutrition
Immobilization
Dietary calcium deficiency
Senile osteoporosis
Excess glucocorticoids
Fibrous osteodystrophy
Called rubber jaw
Excessive resorption of bone that’s replaced w fibrous connective tissue
Common trigger for rubber jaw
Fibrous osteodystrophy
Osteoclastic resorption in response to hyperparathyroidism
Primary hyperparathyroidism
Parathyroid hyperplasia, neoplasia - rare
Secondary hyperparathyroidism
Nutritional imbalance- hyperphophatemia
High phosphorus, low calcium
Renal - decreased renal excretion of phos
Function of PTH in fibrous osteodysplasia
Increased PTH -> binds to osteoblasts, release blasts from surface of bone, stimulate osteoclastic resorption = increased fibrous proliferation
Relation of PTHrP in fibrous osteodysplasia
PTH related peptide - analog of PTH, made in neoplastic cells
Triggered by AGASACA & lymphoma
Can lead to paraneoplastic hypercalcemia
