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PEM Ortho X-ray Curriculum

General Considerations

  • AP lateral at 30 to 45 degrees of flexion, and infrapatellar (sunrise) views 
    • Oblique (at 45° angle) and tunnel views can be considered for special cases
  • AP view identifies accessory ossification centers, osteochondral fractures, and varus/valgus alignments
  • Infrapatellar view (also called horizon view, Merchant's view, tangential or sunrise view) assesses patellar subluxation and dislocation
  • Tunnel view:
    • By flexing the knee, joint surfaces between femur and tibia seen very clearly
    • Two tubercles of intercondylar eminence of the tibia, 1and 2 in Figure 1, can be clearly identified
    • Medial and lateral condylar surfaces may also be seen 3 and 4 in Figure 1
    • Within notch of the joint are the two cruciate ligaments
x-ray showing the joint surfaces between the femur and tibia
FIGURE 1: Tunnel View
    • Ligamentous injuries are commonly due to direct knee trauma or when the knee is subjected to marked valgus and/or varus stress
      • Most frequently injured are the medical collateral and anterior cruciate ligaments
      • Radiographs should be routinely ordered to rule out fractures. Knee injuries in children less than 14 years of age are more commonly seen than ligamentous injuries.