Forearm - AP

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Radiographic Positioning

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Name of projection Forearm - AP
Area Covered Radius, ulna, carpals, distal humerus
Pathology shown Fractures, dislocations,and pathologic processes such as osteomyelitis or arthritis.
Radiographic Anatomy Forearm Radiographic Anatomy
IR Size & Orientation 24 x 30 for smaller patients
35 x 43 cm for larger patients
Portrait, divided in 2 usually fits two forearm views, use lead masking for unused half
Film / Screen Combination Regular
(CR and DR as recommended by manufacturer)
Bucky / Grid No
Filter No
Exposure 54 kVp,
3.2 mAs
FFD / SID 100cm
Central Ray Directed to mid forearm
Perpendicular to IR
Collimation Centre: Midforearm
Shutter A: Including distal humerus to base of the first metacarpal
Shutter B: Skin line
Markers Distal and lateral
Marker orientation AP
Shielding Gonadal (check your department's policy guidelines)
Respiration Not applicable
  • Patient seated close to end of table
  • Elbow fully extended
  • Supinate hand (2nd to 5th metacarpal heads against IR)
  • Entire limb in the same plane
  • Shoulder at table level
  • Align and centre forearm to long axis of IR
  • Check the humeral epicondyles are equidistant from the IR

  • AP positioning of the wrist and hand is demonstrated by:
    1. Styloid of radius is in profile
    2. No or minimal superimposition of the distal radius and ulna
    3. No or minimal super-imposition of the metacarpal bases
  • Humeral epicondyles equidistant to IR is demonstrated by:
    1. Ulnar styloid is posterior to the head of the ulna
  • Proximal ulna super-imposes radial head by about half a centimetre
  • Both epicondyles of humerus are demonstrated in profile at the edges of the distal humerus
  • Capitulum-radius joint is party or entirely closed
  • Radial head articulating surface is demonstrated
  • Olecranon process is within the olecranon fossa
  • Coronoid process is demonstrated on end
  • Radial tuberosity in profile medially
  • Long axis of forearm aligned with long axis of IR
  • Radius and ulna are parallel
  • The radial head, neck, and tuberosity slightly superimposed by the ulna
  • Wrist and elbow joints spaces are open only partially because of beam divergence.
Area Covered

  • Radius, ulna, carpals, metacarpal bases, humeral epicondyles, olecranon fossa
Centre: Midforearm
Shutter A: Including all of the medial epicondyle of the humerus to base of the first metacarpal
Shutter B: Skin line

  • Bony trabecular patterns and cortical outlines are sharly defined
  • Soft tissues are visualised
Special Notes Position the joint closest to the fracture site in true AP


Textbook of Radiographic Postioning and Related Anatomy, Sixth Edition. Authors : Kenneth L. Bontrager, and John P. Lampignano. Copyright 2005 by Mosby, Inc.