Pathology Demonstrated:
- The lateral in either extension or flexion is an alternative to the fan lateral for localization of foriegn bodies of the hand and fingers; it also demonstrate anterior and posterior displaced fracture of metacarpals.
- The lateral in natural flexed position may be less painful for the patient.
Technical Factor:
- IR size - 18 x 24 cm (8 x 10 inches), lengthwise
- Detail screen or digital IR, tabletop
- 55 to 65 kV range
Shielding:
- Place lead shield over patient's lap to shield gonads.
Patient position:
- Seat patient at end of table with elbow flexed about 90degrees and hand and forearm resting on table.
Part Position:
- Rotate hand and wrist, with thumb side up, into a true lateral position, with second to fifth MCP joints centered to IR and CR.
- Lateral in Extension: Extend finger and thumb, and support against a radiolucent support block. Ensure that all fingers and metacarpals are superimposed directly for a true lateral position.
- Lateral in Flexion: Flex finger into natural flexed position, with thumb lightly touching the first finger; maintain true lateral position.
Central Ray:
CR perpendicular to IR, directed to the second to fifth MCP joints.
Minimum SID of 40 inches (100cm)
Collimation:
- Collimate to outer margins of hand and wrist.
Radiographic Criteria:
Structure shown:
Entire hand and wrist and about 2.5cm (1 inch) of distal forearm are visible.
Thumb should appear slightly oblique and free of superimposition with joint spaces open.
Position:
- Long axis of the hand and wrist are aligned with long axis of the IR.
- Hand and wrist should be in a true lateral position, as evidenced by the following: Distal radius and ulna are superimposed; Metacarpals and phalanges are superimposed.
Collimation and CR:
- Collimation should be visible on four sides to area of affected hand.
- CR and center of collimation field should be at second to fifth MCP joints.
Exposure Criteria:
- Optimal density and contrast with no motion demonstrate soft tissue margins and clear, sharp bony trabecular markings.
- Margins of individual metacarpals and phalanges are visible but mostly are superimposed.
