Pathology of Bone Flashcards
What are 3 major roles of bones?
- mechanical support
- protect key organs from traumatic injury
- maintain calcium homeostasis
How are most bones form? Bones found in the skull?
endochondral ossification
intramembranous ossification
Bone structure:
What are other names for Chondrodysplasia/Chondrodystrophy? What is it? What bones are affected?
Chondrodysplasia fetalis or disproportionate dwarfism
breed-associated condition where membranous appositional growth (horizontal) is normal in the bone, but interstitial growth (vertical) of cartilage is abnormal, resulting in premature closure of growth plates and a decrease in the length of long bones
those formed by endochondral ossification
What breed of cattle are most affected by chondrodysplasia? What phenotype results in the most severe form of bovine chrondrodysplasia?
Beef breeds, especially Dexter cattle
homozygote animals for the Dexter phenotype (Dexter “bulldog type” dwarfism) are severely deformed and typically aborted before 7 months of gestation
Dexter bulldog:
tongue seems long because parts of the mandible are derived from endochondral ossification - disproportionate dwarfism - large head with short muzzle - large abdominal hernia
What 5 breeds of dogs exhibit localized chondrodysplasias?
Dachshund and Basset hounds have micromelic achondroplasia
Pugs, Bulldogs, and Boxers exhibit brachycephalic achondroplasia
What is Wobbler’s Syndrome? What are the 2 forms? In what animals is it most common in?
Cervico-Vertebral Stenotic Myelopathy, a localized skeletal dysplasia and degenerative joint disease resulting in compression of the spinal cord
- dynamic: compression of spinal cord occurs no matter the position of the neck
- static: compression of spinal cord occurs when the neck is flexed
horses and large breed dogs, like Great Danes and Doberman Pinschers
Wobbler’s syndrome, spinal cord:
“ski-slope lesion”
- compression causes ataxia and incoordination
Wobbler’s syndrome, neck flexion:
What is Osteopetrosis?
inherited autosomal recessive disease caused by a lack of osteoclasts or by osteoclast failure to reabsorb the primary spongiosa, resulting in an increased bone density and lack of medullary spaces that would hold bone marrow
What is another name for osteopetrosis? What does it tend to cause?
metaphyseal dysplasia
- aplastic anemia, since there is no space for the hematopoietic tissues of the bone marrow to grow
- susceptibility to bone fracture, since the bone is much thicker and less flexible
What does osteopetrosis look like of a radiograph?
much larger and thicker bones that are more radiopaque than usual
(L)
What is congenital cortical hyperostosis? How does this affect fetuses?
autosomal recessive inherited condition in pigs where limbs (primarily the forelimbs) appear swollen due to excessive deposition of radiating trabeculae on the periosteal surface and lymphatic circulation is blocked
born dead or die within hours
What has congenital cortical hyperostosis been compared to in children and young monkeys?
Caffey’s disease - infantile cortical hyperostosis
Congenital cortical hyperostosis:
What is amelia? Hemimelia? Polymelia? Phocomelia? Micromelia?
AMELIA - absence of a limb(s)
HEMIMELIA - absence of the distal half of a limb
POLYMELIA - presence of additional limb(s)
PHOCOMELIA - severe shortening of the long bones of the limbs
MICROMELIA - abnormally small or short limb(s)
What was associated with children born with phocomelia in the 50’s and early 60’s?
pregnant women taking thalidomide (sedative), causing their babies to be born with feet and/or hands close to their trunk, resembling seal flippers
What is syndactyly? Polydactyly?
SYNDACTYLY: fusion of the digits
POLYDACTYLY: presence of extra digits
What are 4 common malformation of the vertebrae? What typically causes them?
- lordosis: ventral deviation of the vertebral column
- kyphosis: dorsal deviation of the vertebral column
- scoliosis: lateral deviation of the vertebral column
4 kyphoscoliosis: dorso-lateral deviation of the vertebral column
a malformed triangular “hemi” vertebrae
Scoliosis, kyphosis, lordosis