Lateral Distal Femur is a radiography positioning projection of the Lower Extremity. Lateral recumbent on affected side. Knee joint included. The centering point is located midway between hip and knee on the affected femur. knee joint must be on the ir.. The central ray is perpendicular to mid femur, centered to include the knee joint.. Image-quality criteria include distal two-thirds of femur including knee joint visible., femoral condyles superimposed in a true lateral position.. Standard exposure ranges from 70 to 80 kVp, 8 to 14 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Distal two-thirds of the femoral shaft.
- Superimposed medial and lateral femoral condyles.
- Patella in lateral profile.
- Knee joint space.
- Trabecular pattern of the distal femur.
Patient preparation
- Verify patient identity using two identifiers.
- Remove radiopaque items from the leg.
- Position patient in lateral recumbent on the affected side.
- Flex the affected knee about 45 degrees.
- Roll the unaffected leg forward and out of the field.
- Confirm pregnancy status when applicable.
Position & centering point
Midway between hip and knee on the affected femur. Knee joint must be on the IR.
Central ray
Perpendicular to mid femur, centered to include the knee joint.
Exposure / technique
- kVp
- 70–80
- mAs
- 8–14
- SID
- 40" (102 cm)
- Notes
- Grid required for adult femur. 14"x17" lengthwise IR. Trauma may use cross-table lateral.
Image-quality criteria
- Distal two-thirds of femur including knee joint visible.
- Femoral condyles superimposed in a true lateral position.
- Knee joint space open between femur and tibia.
- Patella seen in lateral profile anterior to the femur.
- No rotation of the distal femur or knee.
Common errors / ARRT traps
- 1 Improper rotation prevents condylar superimposition.
- 2 Unaffected leg superimposed over the distal femur.
- 3 Knee flexed too much closes the joint space.
- 4 Failure to include the knee joint on the receptor.
Clinical indications
- Lateral view to complement AP distal femur for fracture workup.
- Evaluation of distal femoral shaft pathology.
- Suspected knee pathology referred from the distal femur.
- Post-surgical follow-up of distal femur hardware.
Aligned to the 2025 ARRT Content Specifications.