Bone Pathology Flashcards
What are the cellular elements found in bone?
- Osteoblasts - produce EXC that will become mineralized; younger bone cells; trapped within the Osteoid and become…
- Osteocytes - mature bone cells
- Lining Cells (inactive osteoblasts) - simple squamous epithelium-like; when they become active, they get more “plump” or bigger
- Osteoclasts - multi-nucleated, large cells that reabsorb bone; maintenance of Ca2+ metabolism
Based on the degree of maturity, there are 2 types of bone. What are the 2 types?
- Woven Bone - Immature bone; present during fetal development and in early stages of bone repair
- Lamellar Bone - Mature bone; collagen fibers are arranged in a parallel pattern
Bone formation occurs in 2 ways, both of which involve replacement of Connective Tissue by bone. What are the 2 ways?
- Intramembranous Ossification - occurs within the membranes of condensed primitive mesenchymal tissue –> flat bones of the skull
- Endochondral Ossification - majority of bones in the skeleton; bone develops from a cartilaginous model (hyaline cartilage) that is replaced by osseous tissue
Where does endochondral ossification occur?
The ossification centers of immature bones and in the growth plates (epiphyseal plates) of developing bones.
Longitudinal growth no longer occurs once the growth plates are closed (mature animals). What type of growth is longitudinal growth?
Longitudinal Growth results in an increase in LENGTH.
Growth plates are the site of LONGITUDINAL GROWTH.
Chondrodysplasia is AKA…
Chondrodystrophy, Chondrodysplasia Fetalis or Disproportionate Dwarfism
T/F - Chondrodystrophy is breed-associated, usually hereditary in dogs, cattle and sheep.
True.
What happens in the Anomaly Chondrodysplasia?
Membranous appositional growth is normal but interstitial growth of cartilage is abnormal resulting in premature close of growth plates and decrease length of long bones (affects bones that form by endochondral ossification).
What breeds are more susceptible to chondrodysplasia?
Angus, Hereford cattle
Dexter cattle - Dexter “bulldog” dwarfism
Dexter “Bulldog” is an inherited condition of Dexter cattle. Affected calves are often (fill in blank) and exhibit disproportionate (fill in blank).
Dexter “Bulldog” is an inherited condition of Dexter cattle. Affected calves are often (aborted) and exhibit disproportionate (dwarfism).
What are the CS of Dexter “bulldog”?
Prominent tongue, short vertebral column, marked micromelia - shortening of the limbs
large head with short muzzle
large abdominal hernia
Dachshunds have what type of chondrodysplasia? These breeds exhibit localized chondrodysplasia involving specific bones,
Micromelic achondrodysplasia - short limbs! This is a normal feature in Dachshunds, Bassets, and Corgis. - They are genetically selected to present this!
Brachiocephalic breeds, like PUGS, have what type of chondrodystrophy?
Brachicephalic chondrodysplasia
Bulldogs and Boxers are other breeds with this!
What is Wobbler’s Syndrome?
Cervico-vertebral stenotic myelopathy (degeneration of the spinal cord).
This a localized skeletal dysplasia most common in horses and large breed dogs.
Degenerative joint disease affecting the axial skeleton.
Wobbler’s Syndrome results in what type of compression of the cervical spinal cord?
Dynamic or Static Compression of the Spinal Cord by abnormal cervical vertebrae.
In the Dynamic Form of Wobbler’s Syndrome, spinal cord compression occurs when the neck is…
FLEXED
In the Static Form of Wobbler’s Syndrome, spinal cord compression occurs when the neck is…
Compression occurs no matter what the position of the neck is.
MORE SEVERE FORM!
Osteopetrosis is…
Inherited disease caused by osteoclast failure to reabsorb the primary spongiosa. This failure results in an increased bone density and lack of medullary (bone marrow) spaces.
Osteopetrosis is AKA…
Metaphyseal Dysplasia - results in diffuse osteosclerosis (increased bone density)
Osteopetrosis often presents with…
aplastic anemia - there is no space for the hematopoietic tissues of the bone marrow to grow
Osteopetrosis affected bones are more susceptible to….
Increased susceptibility to fracture.
What is a congenital anomaly in Pigs?
Congenital cortical hyperostosis
Congenital cortical hyperostosis in pigs is what type of condition?
Autosomal recessive inherited condition.
What are the CS of Congenital cortical hyperostosis in pigs?
Forelimbs appear swollen due to excessive deposition of radiating trabecular on the periosteal surface, and blockage of the local lymphatic circulation.
Most pigs are born dead or die within hours.
Congenital cortical hyperostosis in pigs is compared to what disease in children and monkeys?
Caffey’s disease - infantile cortical hyperostosis
What is Amelia?
absence of limb(s)
Hemimelia?
Absence of the distal half of a limb
Polyemia?
Supernumerary limbs
Phocomelia?
Absence of the proximal portion(s) of a limb(s)