Bones 8

• Breeds affected by degenerative intervertebral disk 


  Dachshund, pekingese,corgi
• What are the two types of intervertebral disk disease 


  Acute and chronic
• How does degeneration of intervertebral disk occur

  Degeneration of nucleus pulposus occurs earlier in chondrodystropic breeds ( shot legs long back dogs)

  
  

  
  

  
  

  Largely replaced by dry ,degenerate, often mineralized material by 1 year of age
• How does degeneration of intervertebral disk occur in non chondrodystropic breeds 


  The nucleus pulposus remains gelatinous until middle age then becomes dry but never mineralises
• When does degeneration of annulus fibrosus happen 


  1 year of age in both breeds
• What are features of primary degenerative joint disease 


  • No apparent predisposing cause
  • Mainly occurs in older animals
  • Acceleration of the normal aging process
  • Mild degenerative changes in large weight bearing joints un normal in necropsy
• What is secondary degenerative joint disease 


  • Underlying abnormality in joint or supporting structures leads to premature degeneration
• Possible predisposing factors for secondary degenerative joint disease 


  • Trauma to ligaments
  • Incongruous articular surface eg. Post OCD ,leggings clave , perthe's disease metabolic bone disease
  • Malaligned fractures
  • Septic arthritis
  • Persistent haemarthrosis
• What can cause persistent haemarthrosis 


  warfarin poisoning causes bleeding in the joints
• Gross changes seen in degenerative joint disease 


  • Yellow discoloration of articular cartilage
  • Fibrillation- roughening of articular cartilage
  • Eburnation- Loss of articular cartilage and sclerosis of exposed subchondral bone
  • Pannus formation- extension of granulation tissue over articular cartilage from synovial membrane
  • Osteophyte formation-nodular bony outgrowth around margin of articular cartilage and bone
• Other gross changes in degenerative joint disease

  Fibrosus thickening of joint capsule

  Hypertrophy of synovial villi

  Excess synovial fluid
• What change is seen here

  Fibrillation

  
• What gross lesion is this

  Fibrillation

  
• Name the lesion

  Osteophyte

  
• How do fibrocartilarginous embolism occur 


  It happens when degenerate material from nucleus pulposus gains access to the spinal vasculature leading to infarction of spinal cord