Forearm (horizontal beam lateral view)

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

Indications

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 position

  • patient is seated alongside the table
  • the medial border of the extended elbow and palmar aspect of the forearm are kept in contact with the detector (see Figure 2)
  • detector is medial to the forearm

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
    • 50-60 kVp
    • 3-5 mAs
  • SID
    • 110 cm
  • grid
    • no

Image technical evaluation

  • the elbow joint is in AP position with little to no superimposition
  • the wrist joint is in lateral position

Practical points

Contrary to popular belief the lateral forearm should not be considered a view to evaluating any occult injuries of the wrist joint and or elbow due to beam divergence. Beam divergence at the edges of the image should be acknowledged when assessing anatomy (see Figure 1) .