What is the recommended imaging protocol for a forearm X-ray (X-ray) request?

Standard Forearm X-Ray Protocol

For a forearm X-ray request, obtain anteroposterior (AP) and lateral views as the standard two-view series, with the forearm positioned so the radius and ulna are parallel to the imaging table. 1

Standard Positioning and Views

Required Views

• AP view: Position the forearm with the elbow extended and forearm fully supinated (palm up), ensuring the radius and ulna are parallel to each other and perpendicular to the X-ray beam 2
• Lateral view: Position with the elbow flexed at 90 degrees and the forearm in true lateral position (thumb up) 1, 3

Key Technical Points

• The radius and ulna should be centered and parallel to the short axis of the imaging table 4
• Include both the wrist and elbow joints on the images when clinically indicated to assess for associated injuries 1
• Ensure no rotation of the forearm during imaging, as this can obscure fracture lines and alignment 2

When to Add Oblique Views

Add oblique views when initial AP and lateral views are equivocal or when clinical suspicion remains high despite normal two-view radiographs. 5

• Oblique views increase diagnostic confidence and uniquely reveal abnormalities in 4.8% of cases, particularly changing equivocal findings to definitive positive or negative interpretations 5
• This additional view is equally valuable across all distal extremity sites including the forearm 5

Clinical Context Considerations

Trauma Cases

• For acute forearm trauma, the two-view series (AP and lateral) should be obtained first to assess for fractures, dislocations, or joint effusions 1, 3
• Pay particular attention to soft tissue swelling on conventional radiographs, as this may be key for correct diagnosis 3
• If radiographs are normal but clinical suspicion for fracture remains high, CT without contrast is the next appropriate study 1

Specific Injury Patterns to Assess

• Monteggia fractures: Verify the radiocapitellar line passes through the capitellum on both AP and lateral views; the line through the midpoints of the proximal and distal radial physes (P-line) is most reliable, especially in children 6
• Essex-Lopresti injuries: Ensure both forearm and wrist are included to assess for radial head fracture with distal radioulnar joint disruption 4
• Distal radius fractures: Standard two-view radiographs are usually sufficient, but four views of the wrist may be needed if distal involvement is suspected 3

Common Pitfalls to Avoid

• Do not accept rotated views: Supination provides the smallest AFR-RNA angle and best approximates native anatomy; improper rotation can mask fractures 2
• Do not miss soft tissue signs: Carefully examine soft tissues on conventional radiographs for swelling, fat pad displacement, or foreign bodies 3
• Do not order advanced imaging first: Plain radiographs must be obtained before CT or MRI, as they are universally available, inexpensive, and usually sufficient for diagnosis 3
• Do not forget to include joints: When trauma mechanism suggests proximal or distal extension, include the adjacent joint to avoid missing associated injuries 1

Follow-Up Imaging Indications

• CT without contrast: For occult fractures when radiographs are normal but clinical suspicion persists, or for preoperative evaluation of complex comminuted fractures 1, 3
• MRI without contrast: For suspected soft tissue injuries (tendons, ligaments, nerves) when radiographs are normal or indeterminate 4, 1, 3