Bones

• Cortical, long or tubular bones
  

_Epiphysis
_Metaphysis
_Diaphysis
_Enchondral ossification
_Compact vs trabecular(spongy) bone

• Membranous, flat bones
• Intramembranous ossification
   
  Functions
  
• Hematopoietic factory
• Mineral reservoir
• Structural protection
• Support and levers for locomotion
   
  Cells
• Osteoblast
• Osteocyte
• Osteoclast
• Wolff’s Law
  _Remodeling
   
  Development
• Complex; genes regulate body form
• Defects in mineralization or matrix
• Achondroplasia
• Osteopetrosis
• Osteogenesis imperfecta
    
  Metabolic Bone Disease
• Osteomalacia (soft bones)
  _Vitamin D
      *Require processing in liver and kidney
      *In diet and synthesized (sun)
      *Absorption of calcium decreased
      *Serum calcium falls
      *Parathormone increased
      *Calcium mobilized from bone
      *Renal excretion reduced
      *Phosphate excretion increased
   
  Deficiency
• Intake too low
  _  In malnourished children: Rickets
•      Abnormal absorption
• Abnormal metabolism
  _  Kidney disease (also liver)
       *Renal osteodystrophy
• SYMPTOMS
  _ Bone pain
  _  Weakness
   
  Osteoporosis
• Inevitable consequence of aging
• Complication of estrogen level change (menopause)
• Two types
  _  Primary (aging): loss of osteoblasts
  _ Secondary
     *Hormonal (estrogen: osteoclastic)
     *Dietary
     *Disuse (sedentary; immobilization)
     *Drugs and Tumors
    
  Osteoporosis             
   An Osteopenia
• Matrix and mineral lost
• Critical growth to age 30
• Lose 0.5%/year; 3-5x in woman
• Calcium intake, exercise, genes
• Fractures: where?
• Detection
• Treatment
   
  Paget’s Disease
• Common, 2-4%
• Local vs generalized
• Likely viral
• Skull and legs common
• Bone pain
• Imbalanced bone remodeling
• Complication: osteosarcoma
   
• Osteonecrosis
  _  Infarct of bone
  _  Children (slipped epiphysis)
• Osteomyelitis
  _  Infection
       *Exogenous (trauma, surgery)
  •    Soft tissue symptoms
       *Endogenous (hematogenous)
  •    Insidious development, pain
       *Difficult to treat
   
  Fractures
• 
  Natural(traumatic) and pathologic
• Types
  _ Displaced, comminuted, spiral, etc.
  _   Greenstick, bowing, torus, stress
• Healing: callus
• Nonunion: pseudoarthrosis
  _  Infection
   
  Tumors
• Metastatic
  _  Prostate
  _  Breast
  _  Lung
  _ Kidney
• Osteosarcoma
• Multiple myeloma
   
  Joints
• Capsule
• Tendons
• Ligaments
• Synovium
• Bursae
• Types
  _  Teeth
  _  Skull
  _  Spine
   
  Osteoarthritis
• Degradative, not inflammatory
• Increases with age
  _  65,000,000
• Hip, knee, hand(IP),spine
• Primary
• Secondary
  _ Metabolic: acromegaly, hemophilia
  _  Anatomic: congenital dislocation
  _  Trauma: jackhammer, sports
  _  Neuropathies: diabetes
• Pathology
  _  Loss of cartilage
      *Enzymatic destruction
       *Fibrillation
       *Eburnation
       *Cystic change
  _  Reactive bone: osteophytes
       *Joint mice
   
  Rheumatoid Arthritis
• Inflammatory, autoimmune
• Serologic test: rheumatoid factor
• Adult and childhood forms
• Peripheral joints, systemic
• 1-2%, temperate more than tropic
• genetic factors (HLA)
• pannus, ankylosis
• tendons, contractures
   
  Others
• Lyme Disease
  _  erythema marginatum
  _  erythema chronicum migrans
• Degeneration of the intervertebral discs
• Gout
  _  Hyperuricemia (purines)
  _ Crystals phagocytosed by PMNs
  _ Tophi, kidney stones
  _  Acute versus chronic
   
  Reactive Arthritis
•  Ankylosing Spondylitis
• Spondylitis
  _  Inflammatory bowel disease
  _  Psoriasis
  _  Reiter’s syndrome
   
  Left Overs
• Joint Replacement
• Subluxation and Dislocation
• Strains = tendon/muscle tears
• Sprains= ligament tears
• Tendinitis
• Bursitis
• Epicondylitis
  _  Lateral: tennis
  _  Medial: golf
   
  Autoimmune
• Rheumatic Diseases
• Scleroderma (Progressive Systemic Sclerosis)
  _  Raynauds
• Lupus erythematosus
  _ Systemic vs discoid
  _  Antinuclear antibody, Anti-DNA
   
  Muscle Disease
• Dermatomyositis
• Muscular Dystrophies
  _  Duchenne’s (dystrophin)
  _  Myotonia
• Myasthenia gravis
• Trichinosis
• Polymyositis
  _  Cancer associated