Femur (lateral view)

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The lateral femur view is part of a standard series examining the femur in its entirety, including the hip and knee joint. Due to the limitations of the image detector, these projections are often performed in two images per view to ensure inclusion of both knee and hip joints.

Indications

This view demonstrates the femur in an orthogonal position to the AP view. This allows assessment of suspected dislocations, fractures, localizing foreign bodies and osteomyelitis within the long bone. Depending on departments, this view can be crucial for orthopedic surgeons to determine the length of the femur for prosthetic purposes.

Patient position

  • the patient is rolled at least 45° onto the side of interest
  • the unaffected leg is bent to stabilize the patient position i.e. foot firm on the bed to ensure stability 
  • if acquiring the entire femur in one image, place the detector in a diagonal position parallel with the femur

Technical factors

  • anteroposterior projection
  • centering point
    • for one image: mid femur region
    • for two images: 
      • proximal femur: place detector to include anatomy from ASIS to mid-femoral shaft
      • distal femur: place detector to include anatomy from mid-femoral shaft to knee joint
      • to ensure overlap of anatomy, a physical side marker can be positioned at mid-femur region
  • collimation
    • laterally to the skin margins
    • superior to ASIS
    • inferior to proximal third of tibia/fibula
  • orientation  
    • portrait
  • detector size
    • 30 cm x 43 cm
  • exposure
    • 65-70 kVp
    • 8-12mAs
  • SID
    • 100 cm
  • grid
    • yes

Image technical evaluation

  • greater and lesser trochanters should be superimposed by the femoral neck
  • a small part of the lesser trochanter is visible medially
  • anterior and posterior margins of the femoral condyles should be superimposed

Practical points

  • for orthopedic requests of full femur length in one image, understanding the anatomy of the pelvic girdle and hip joint well can help in positioning the detector diagonally to include as much of the hip joint and its inferior components