Lower Leg (Tibia and Fibula) Projections

Patient Preparation

• Explain the procedure to the patient.
• Remove any clothing, shoes, or metallic objects from the area of interest.
• Ensure the patient is comfortable and immobile during exposure.
• Use lead shielding as appropriate.

BASIC PROJECTIONS

1. Anteroposterior (AP) Projection — Lower Leg

Positioning:

• Patient supine with the leg fully extended.
• Foot dorsiflexed so that the plantar surface is vertical (perpendicular to the IR).
• Ensure femoral condyles are parallel to the IR.
• Center the lower leg (tibia and fibula) to the midline of the IR.

Central Ray (CR):

• Perpendicular to the IR.
• Directed to the midpoint of the lower leg.

Collimation:

• Include both knee and ankle joints.

Evaluation Criteria:

• Entire tibia and fibula visualized.
• Knee and ankle joints partially open.
• Slight overlap of proximal and distal ends of tibia and fibula.
• No rotation — femoral condyles in profile.

2. Lateral (Mediolateral) Projection — Lower Leg

Positioning:

• Patient lies on affected side.
• Opposite leg placed behind or in front for support.
• Knee may be slightly flexed.
• Ensure the leg is in a true lateral position — femoral condyles superimposed.
• Dorsiflex the foot.

Central Ray (CR):

• Perpendicular to the IR.
• Directed to the midpoint of the lower leg.

Collimation:

• Include both knee and ankle joints.

Evaluation Criteria:

• Entire tibia and fibula visualized.
• Tibial tuberosity in profile.
• Distal fibula superimposed over posterior half of tibia.
• Clear visualization of knee and ankle joints.

OTHER PROJECTIONS

3. AP Oblique Projection — Lower Leg

Positioning:

• Patient supine with leg extended.
• Rotate the leg medially or laterally 45°, depending on area of interest.
  • Medial rotation: Demonstrates proximal and distal tibiofibular joints.
  • Lateral rotation: Demonstrates fibula superimposed by tibia.

Central Ray (CR):

• Perpendicular to the IR.
• Directed to the midpoint of the lower leg.

Collimation:

• Include knee and ankle joints.

Evaluation Criteria:

• Appropriate rotation demonstrated by partial or full separation of tibia and fibula.
• Sharp bony detail with no motion.
• Entire lower leg visualized.

Image Evaluation Checklist

• Proper exposure and contrast.
• Both knee and ankle joints visible.
• No motion or artifacts.
• Anatomical markers correctly placed.

Common Pathologies Demonstrated

• Fractures of tibia or fibula (proximal, midshaft, or distal).
• Bone lesions and infections.
• Alignment and rotational deformities.