PA PROJECTION - RADIAL DEVIATION: WRIST
Warning:
- If patient has possible wrist trauma, do not attempt this position before routine wrist series has been completed and evaluated to rules out possible truama of distal forearm and/or wrist
Pathology Demonstrated:
- Fractures of the carpal bones on the ulnar side of the wrist, specially the lunate, triquetrum, pisiform, and hamate, are demonstrated.
Technical Factors:
- IR size - 18 x 24 cm (8 x 10 inches)
- Division in half, crosswise
- Detail screen, tabletop
Digital IR - use lead masking - 60 or add upto 6kV range
Shielding:
- Place lead shield over patient's lap to shield gonads
Patient Position:
- Seat patient at end of table, wrist and hand on cassette, and palm down, with shoulder, elbow, and wrist on same horizontal plane.
Part Position when Performing wrist x-ray:
- Position wrist as for PA projection - palm down with wrist and hand align with center of long axis of portion of IR being exposed.
- Without moving forearm, gently invert hand (move medially toward thumb side) as far as patient can tolerate without lifting or rotating distal forearm.
Central Ray:
- CR perpendicular to IR, directed to midcarpal area
- Minimum SID of 40 inches (100cm)
Collimation:
- Collimate on four sides to carpal region.
Radiographic Criteria of Posteroanterior (PA) Wrist:
Structure shown:
- The distal radius and ulna, the carpals, and the proximal metacarpals are visible.
- The carpals are visible, with adjacent interspaces more open on the medial (ulnar) side of the wrist.
Position:
- The long axis of the forearm is aligned with the side border of the IR.
- Extreme radial deviation is evidenced by the angle of the long axis of the metacarpals to that of the radius and ulna and the spaces between the triquetrum/pisiform and the styloid process of the ulna.
- No rotation of the wrist is evidenced by the appearance of the distal radius and ulna.
Collimation and CR:
- Collimation should be visible on four sides to the area of the affected wrist.
- CR and center of the collimation field should be to the midcarpal area.
Exposure Criteria:
- Optimal density and contrast with no motion visualize the carpal borders and clear, sharp bony trabecular markings.
