Anatomy

• Which bones form the proximal and distal rows of the wrist?
  The proximal row (lateral to medial) includes the scaphoid, lunate, triquetrum, and pisiform.
  The distal row includes the trapezium, trapezoid, capitate, and hamate.
• Which bones articulate at the radiocarpal (wrist) joint?
  The distal radius articulates with the scaphoid and lunate; the ulna does not directly articulate but connects via the triangular fibrocartilage complex (TFCC).
• What carpal bone forms the floor of the anatomic snuffbox, and why is that important?
  The scaphoid; tenderness in this area is a clinical sign of a possible scaphoid fracture.
• Which carpal articulates with the base of the first metacarpal?
  The trapezium, forming the thumb carpometacarpal joint that allows opposition and flexion-extension.
• Which carpal bone contains a hook-like process, and what is its clinical significance?
  The hamate; the hook (hamulus) is often involved in fractures visible on the Gaynor-Hart projection.

Positioning

• Why are the fingers flexed for a PA wrist projection?
  Flexing the fingers reduces OID by bringing the carpals into direct contact with the IR, improving spatial resolution.
• Why is the hand rotated laterally 45° for a PA oblique wrist?
  To demonstrate the lateral carpals (trapezium and scaphoid) with minimal overlap of adjacent bones.
• Why is a foam wedge often used for the oblique projection?
  It standardizes the 45° angle and prevents over-rotation or collapse of the wrist position during exposure.
• Why is the elbow flexed 90° for the lateral projection?
  To align the radius and ulna vertically and achieve true superimposition without pronation or supination errors.
• Why is ulnar deviation used for scaphoid imaging?
  It elongates the scaphoid and opens joint spaces between the scaphoid and adjacent carpals to better reveal fractures.
• Why is the CR angled 10–15° proximally for a PA ulnar deviation view?
  This projects the scaphoid free of self-superimposition and enhances visibility of fracture lines.
• Why is the IR angled 20° for the Stecher method?
  The angled IR makes the scaphoid perpendicular to the beam, minimizing foreshortening without requiring tube angulation.
• Why is the wrist hyperextended and CR angled 25–30° for the Gaynor-Hart (carpal canal) projection?
  To tangentially project the carpal tunnel, separating the pisiform and hamulus for visualization of tunnel pathology.

Technique & Image Evaluation

• How can you tell a PA wrist is not rotated?
  There is equal concavity of the metacarpal shafts, equal spacing between proximal metacarpals, and minimal overlap at the distal radioulnar joint.
• How can you tell a PA oblique wrist was correctly positioned at 45°?
  The trapezium and distal scaphoid are visualized with minimal superimposition, and the 3rd–5th metacarpal bases are partially overlapped.
• How can you tell the lateral wrist is truly lateral?
  The distal radius and ulna are perfectly superimposed, and metacarpals 2–5 overlap completely.
• How can you tell there was adequate ulnar deviation on a scaphoid view?
  The scaphoid appears elongated with open joint spaces, and the long axis of the metacarpals forms a wide angle with the radius and ulna.
• How can you tell the CR angle for the PA axial (Stecher) was correct?
  The scaphoid is seen without foreshortening, and adjacent carpal articulations are clearly open.
• How can you tell a Gaynor-Hart projection is properly positioned?
  The pisiform is in profile and separated from the hamulus; the carpal bones form a distinct arch representing the canal.
• How do you identify motion or poor technique?
  Cortical bone margins and trabecular detail appear blurred; repeat with improved immobilization or shorter exposure time.
• How do you know the exposure technique was adequate for DR imaging?
  Soft-tissue outlines and fine trabecular patterns are visible without saturation; brightness and contrast are consistent across carpal and distal radial regions.

Clinical Applications

• Which projection is best to evaluate a suspected scaphoid fracture when routine views are inconclusive?
  PA ulnar deviation with 10–15° proximal CR angle and/or PA axial (Stecher) projection.
• Which projection demonstrates the carpal tunnel for suspected median nerve impingement?
  Tangential carpal canal (Gaynor-Hart).
• Which projection helps assess anterior or posterior displacement in Colles’ or Smith fractures?
  Lateral wrist projection.
• Why might the Rafert-Long series be performed after a negative routine wrist exam?
  To assess the scaphoid at multiple CR angles (0°, 10°, 20°, 30°) for subtle, non-displaced fractures invisible on standard views.