Forearm (AP view)

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

Indications

This view demonstrates the elbow joint in its natural anatomical position allowing for assessment of suspected dislocations or fractures and localizing foreign bodies within the forearm.

Patient position

  • patient is seated alongside the table
  • forearm is supinated, and its dorsal surface is kept in contact with the cassette with extension at the elbow joint
  • both elbow joint and wrist joints are also kept in contact with the cassette

Technical factors

  • anteroposterior 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
    • 100 cm
  • grid
    • no

Image technical evaluation

  • trochlea and capitulum being seen in profile. 
  • the wrist is in AP position, with minimal superimposition of the distal radius and ulna.
  • the arm should be extended appropriately, as evidenced by the radial head being seen in profile.

Practical points

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