Bone Pathology

• Fill in the blanks

  A) Epiphysis

  B) Diaphysis

  C) Epiphysis

  D) Articular cartilage

  E) Medullary trabecular bone

  F) Compact cortical bone

  G) Periosteum

  H) Medullary cavity

  I) Articular cartilage

  
• Fill in the blanks

  A) cortical

  B) blood vessels

  C) osteocytes

  D) bone lamellae

  E) Haversian

  F) Trabecular

  G) osteocytes

  H) bone lamellae

  I) marrow

  
• Medullary bone

  E.g. vertebral bodies & ends of long bones

  Similar structure to cortical bone

  • lamellae run parallel to bone surface

  
• Cortical bone

  E.g. diaphysis of long bones

  Arranged in Haversian systems (series of concentric lamellae of collagen fibres surrounding central canal of blood vessels)

  
• Woven bone

  Produced rapidly (e.g. foetal development, fracture repair)

  Haphazard arrangement of collagen fibres (less structural integrity)

  
• Functions of bone

  Mechanical support & movement

  Protection of internal organs

  Mineral homeostasis

  Haematopoiesis
• What pathways lead to increased osteoclast differentiation?

  RANK-RANKL

  M-CSF
• What pathways lead to reduced osteoclast differentiation?

  Wnt signalling

  -> stimulates osteoBLASTs to osteoprotegerin (OPG) synthesis
• Role of sex steroids in bone health

  Oestrogen

  • promote osteoblast
  • stimulates apoptosis of osteoclasts
  • = promotes bone formation & calcium uptake in gut

  Androgen

  • local conversion to oestrogens (anabolic in bone)

  Glucocorticoids

  • promotes osteoclast activity & inhibits calcium uptake in gut
• What is the treatment of fat embolism (following a long bone fracture)?

  Supportive management
• Benign bone forming tumours

  Osteoid osteoma

  • < 2cm
  • common in young men
  • common in femur & tibia
  • presentation = nocturnal bone pain relieved by NSAIDs
  • treatment = radiofrequency ablation

  Osteoblastoma

  • > 2cm
  • common in posterior spine
  • treatment = curettage or en bloc excision
• What is the most common primary malignant tumour of bone?

  Osteosarcoma
• Osteosarcoma

  Primary malignant tumour of bone

  Bimodal occurrence (75% before 20 yrs)

  Tumours commonly arise in metaphyseal region of long bones

  Symptoms = bone pain, pathological fractures

  Treatment = neoadjuvant chemo + surg resection + post-op adjuvant chem
• What is shown in the image?

  Osteosarcoma on XR

  
• What is shown in the image?

  Osteosarcoma

  
• What is shown in the image?

  Osteosarcoma

  
• Types of osteoporosis

  Post-menopausal

  Senile