Forearm (PA view)

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The posteroanterior 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 PA view of the radius and lateral view of the ulna.

Patient position

  • patient is seated alongside the table
  • with 90° elbow flexion, the palmar aspect of the forearm from wrist to elbow are kept in contact with the receptor, ensuring the same horizontal plane (see Figure 2)

Technical factors

  • posteroanterior 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 true lateral position
  • the wrist joint is in PA position with little to no superimposition

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) .