Pediatric forearm (lateral view)

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The lateral forearm view for pediatrics is one of two standard projections in the forearm series to assess the radius and ulna.

Indications

This view allows for the assessment of suspected dislocations or fractures and localizing foreign bodies within the forearm.

However, this view should not be considered when evaluating occult wrist or elbow injuries due to beam divergence (see Figure 1). Beam divergence at the edges of the image should be acknowledged when assessing anatomy .

Patient position

  • patient is seated alongside the table
  • at 90° elbow flexion, the medial border of the arm and forearm are kept in contact with the receptor, ensuring the same horizontal plane
  • rotate the hand and wrist externally to achieve a true lateral position

Technical factors

  • 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
    • 50-55 kVp
    • 1.6-2 mAs
  • SID
    • 110 cm
  • grid
    • no

Image technical evaluation

  • the distal radius and ulna should be superimposed
  • the trochlea and capitellum should be superimposed with the radial head being seen in profile

Practical points

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.

To ensure true lateral through out the entire forearm, encourage patients' hand and wrist into a lateral position by instructing them to give you a "thumbs up" gesture and pointing their thumb perpendicular to the ceiling.

Immobilization techniques

To prevent malrotation/motion artifact 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 .