Pediatric tibia fibula (AP view)

Last revised by Amanda Er on 27 Mar 2023

The pediatric tibia fibula anteroposterior view is part of a two-view series of the entire tibiafibula, and both the knee and ankle joint. 

The tibia fibula AP view is performed for evaluation of the lower leg in pediatric patients. It allows for assessment of fractures in trauma or suspicion of a foreign body or bone lesions, including osteomyelitis. If one is concerned about the ankle joint, the ankle series is more appropriate, if the knee is the point of focus, a knee series.

  • the patient may be supine or sitting upright with their leg extended on the table

  • the foot is in dorsiflexion with the toes pointing directly toward the ceiling

  • anteroposterior projection 

  • centering point

    • midpoint of the tibia

  • collimation

    • laterally to the skin margins

    • superior to the knee joint

    • inferior to the ankle joint

  • orientation

    • portrait or diagonal depending on limb length  

  • detector size

    • 35 cm x 43 cm or 43 cm x 35 cm

  • exposure 

    • 55-60 kVp

    • 1-3 mAs1

  • SID

    • 100 cm

  • grid

    • no

  • tibia superimposes about one fourth of the fibular head, and about half of the distal fibula

  • mid shaft of the fibular is free of superimposition with the tibia

  • tibia and fibula are demonstrated in the AP position in their entirety from the knee joint to the ankle

  • lateral and medial malleoli of the distal fibula and tibia are in profile

  • tibiotalar joint space and the knee joint space are open2

Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is important as pediatric patients may not remain still when their affected leg is moved onto the detector. 

In some cases where the patient's limb does not fit in one image, it is better to take two images at both points than perform a sub-par projection in the center. If both the ankle and the knee joints are not present it is not a complete series.

It is important to avoid repeated x-rays and for the radiograph to be free of motion artifact and rotation.

  • it may be necessary for the parent or radiographer to hold the patient in position

  • ideally the parent should be in the child's direct line of sight

  • techniques will vary based on the department

  • distraction techniques can be utilized to avoid scattered radiation to parents and staff 3

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Cases and figures

  • Case 1: normal
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  • Case 2: normal
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