Musculoskeletal imaging

• Imaging of musculoskeletal trauma
  • X-ray first
    • 2 directions are always needed!
      • Fractures are often visible in only one direction, so we need 2 x-rays from different perpendicular directions to evaluate
    • Evaluation of x-ray
      • Anatomical shape, form and alignment
      • Cortex and medullary structure
        • Medulla should have trabecular pattern
      • Surface of joint
      • Surrounding soft tissues
      • In children
        • Epiphyseal plates
    • Fracture
      • -> one part of the bone is displaced compared to the rest of the bone
      • If the distal part of the bone is displaced dorsally compared to the proximal part due to a fracture, it’s a dorsal fracture
    • Fat blood interface sign (FBI sign)
      • Horizontal fluid level outside the bone that forms as blood and bone marrow fat escapes during a fracture
    • Rule of 2s
      • Get 2 x-rays with perpendicular directions
      • Image 2 joints (proximal and distal to the injury)
      • Get images at 2 occasions
      • Get images of 2 limbs – for comparison
  • Then US/CT/MRi
  • CT
    • For complex fractures/tumors
    • Interverterbral discs
  • MRi
    • Best for soft tissue
    • Bone does not give signal on MRi, but fatty bone marrow is visible
    • For inflammatory processes, tumors, sports injuries (often involve ligaments and not bones)
• Sesamoid bones
  • Can be present as a variant of normal anatomy or as a response to strain
  • Often embedded in tendons
• Specific pathologies
  • Meniscus tear
    • MRI
  • Polytrauma
    • CT
  • Weber fracture (types of ankle fracture)
    • Weber A – Fibula fracture under the syndesmosis with tibia
    • Weber B – Fibula fracture at the level of the syndesmosis with tibia
    • Weber C – Fibula fracture above the syndesmosis with tibia
  • Don Juan fracture
    • Fracture of calcaneus
  • Shoulder
    • Fracture often accompanies dislocation
      • Dislocation -> head of the humerus ends up behind the coracoid process
    • Fracture of surgical head of the humerus is the most common
    • AP front-facing position