Pediatric forearm (horizontal beam lateral view)

Last revised by Andrew Murphy on 23 Mar 2023

The horizontal beam lateral forearm view for pediatrics is one of two modified trauma projections in the forearm series, examining the radius and ulna. 

This view is ideal for patients who are unable to move their arm as per the standard forearm positioning technique but require assessment of suspected radius and/or ulna dislocations or fractures. This shows a lateral view of the radius and AP view of the ulna.

  • patient is seated alongside the table
  • the medial border of the extended elbow and palmar aspect of the forearm is kept in contact with the detector (see Figure 1)
  • detector is medial to the forearm
  • lateral projection
  • centering point
    • mid forearm region
  • collimation
    • distal to the wrist joint 
    • proximal to elbow joint
  • orientation  
    • portrait
  • detector size
    • 24 cm x 30 cm
  • exposure 1
    • 50-55 kVp
    • 2-4 mAs
  • SID
    • 110 cm
  • grid
    • no
  • the elbow joint is in AP position with little to no superimposition
  • the wrist joint is in a lateral position

Contact lead shielding is no longer recommended for any pediatric examination. Statements have been released by several radiological societies supporting an end to this practice 2-5, with the most comprehensive guidance statement on this matter being in an 86-page joint report 6.

Please see your local department protocols for further clarification as they may differ from these recommendations.

Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is extremely beneficial for forearm imaging as young children may begin to cry the moment their affected arm is brought away from their body.

If the patient is seated, it may be ideal to elevate the patient's forearm by having a flat radiolucent sponge placed medially (see Figure 1). This ensures the palmar soft tissue margin of the forearm is included, especially when the detector is positioned on the same tabletop as the patient's forearm.

As with trauma imaging, preparing the room for a horizontal beam image may not always be the first line of action. Having clear positioning instructions prepared and all immobilization devices (i.e. radiolucent sponges, detector holder) within reach may be useful in obtaining the image efficiently.

To prevent malrotation/motion artefact in the radiograph, parental holding at the proximal half of the child’s arm and distal part of the hand may be required. Other alternative methods such as distraction techniques may be ideal to avoid scattered radiation to parents and staff 7.

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Cases and figures

  • Figure 1: radiographic positioning
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  • Case 1: torus fracture
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  • Case 2: bowing forearm fracture
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