Femur - LateralThis is a featured page

Radiographic Positioning


Adult
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Name of projection Femur - Lateral

This table looks at the proximal femur. See table below for the distal femur.

The lateral femur image must cover the entire femur including the hip joint and the knee joint.

If the entire femur cannot be included in a single image, two must be taken with a minimum of 5 cm (2 inches) overlap. The size of the second IR will depend on the coverage required. In this case it may be simply an lateral knee
Area Covered Proximal half to two thirds of femoral shaft, femoral head, femoral neck, trochanters, hip joint
Pathology shown Fractures, lesions
Radiographic Anatomy Femur Radiographic Anatomy
IR Size & Orientation 35cm x 43cm
Portrait
Film / Screen Combination Regular
(CR and DR as recommended by manufacturer)
Bucky / Grid Moving or stationary grid
Filter No
Exposure 70 kVp
16 mAs
FFD / SID 100cm
Central Ray Directed to mid-femur
Perpendicular to IR
Collimation Centre: align the upper edge of the IR to the level of the anterior superior iliac spines (ASIS's)
Shutter A: to the full length (43 cm or 17 inches) of the IR
Shutter B: within 1.25cm (half an inch) of the skin-line
Note: the position of the proximal and mid femoral shaft is nearer the anterior aspect of the thigh
Markers Lateral to mid-femur shaft
Marker orientation is AP
Shielding Not usually possible as gonadal shielding may obscure essential anatomy
(check your department's policy guidelines)
Respiration Not applicable
Positioning
  • Patient supine
  • Roll patient onto affected side until the femur is against the table and the femoral epicondyles are perpendicular to the table
  • The pelvis will be about 10 to 15 degrees posterior from the lateral position
  • Unaffected limb behind and supported on sand-bags
Critique

Positioning
  • Lateral postioning of the proximal femur is evidenced by
    • Femoral shaft is demonstarated without foreshortening
    • Femoral neck is seen on end
    • Greater trochanter should be beneath femoral neck
  • Trochanters are not prominent
  • Femur is centred to field
  • Majority of the femur is visualised
  • No super-imposition of opposite thigh
Area Covered
  • Proximal half to two thirds of femoral shaft, femoral head, femoral neck, trochanters, hip joint
Collimation
  • Centre: align the upper edge of the IR to the level of the anterior superior iliac spines (ASIS's)
    Shutter A: to the full length (43 cm or 17 inches) of the IR
    Shutter B: within 1.25cm (half an inch) of the skin-line
Exposure
  • Trabecular markings on femoral shaft are visualised
Special Notes Effect of incorrect rotation
  • If greater trochanter is shown laterally this indicates that the patient was not rotated enough
  • If the greater trochanter is shown medially, the leg was over rotated

  • If orthopaedic devices are present they should be included in entirety


Name of projection Femur - Lateral

This table looks at the distal femur. See table above for the proximal femur.

The lateral femur image must cover the entire femur including the hip joint and the knee joint.

If the entire femur cannot be included in a single image, two must be taken with a minimum of 5 cm (2 inches) overlap. The size of the second IR will depend on the coverage required. In this case it may be simply a rolled lateral hip


---- Under Construction ---
Area Covered Distal 2/3rds of femoral shaft, patella, proximal tibia and fibula, knee joint
Pathology shown Fractures, lesions
Radiographic Anatomy Femur Radiographic Anatomy
IR Size & Orientation 35cm x 43cm Portrait
Film / Screen Combination Regular
(CR and DR as recommended by manufacturer)
Bucky / Grid Moving or stationary grid
Filter No
Exposure 70 kVp
16 mAs
FFD / SID 100cm
Central Ray Directed to mid-femur
Perpendicular to IR
Collimation Centre: align the lower edge of the IR to 5cm (2 inches) below the knee joint
Shutter A: to the full length (43 cm or 17 inches) of the IR
Shutter B: within 1.25cm (half an inch) of the skin-line
Markers Lateral to mid-femur shaft
Marker orientation is AP
Shielding Gonadal
(check your department's policy guidelines)
Respiration Not applicable
Positioning
  • From the supine position, roll the patient onto the affected side until the pelvis is lateral
  • The femoral epicondyles should be perpendicular to the IR
  • Flex the knee about 45 degrees
  • Support unaffected leg at hip level
Critique

Positioning
  • Femoral condyes will not be super-imposed due to divergent rays, but
    • the anterior and posterior margins of the condyles should line up
    • the medial condyle will be projected distally, due to beam divergence, closing the knee joint space
  • Femoropatellar joint space
  • Patella in profile
  • Fibula head beeath tibia
Area Covered
  • Distal 2/3rds of femoral shaft, patella, proximal tibia and fibula, knee joint
Collimation
  • Centre: align the lower edge of the IR to 5cm (2 inches) below the knee joint
    Shutter A: to the full length (43 cm or 17 inches) of the IR
    Shutter B: within 1.25cm (half an inch) of the skin-line
Exposure
  • Trabecular markings on femoral shaft should be visualised
Special Notes Mispositioning is assessed by viewing the anterior and posterior margins of the condyles
  • one condyle anterior to the other is indicative of under or over rotation
  • to determine which way indentify the condyles
  • Due to divergent rays the distal condyle is the medial condyle

If a fracture is suspected, this projection can be achieved in the supine position using a horizontal ray with the IR against the medial aspect of the affected femur




AndyC
AndyC
Latest page update: made by AndyC , May 12 2011, 3:00 AM EDT (about this update About This Update AndyC Edited by AndyC

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