"FAN" LATERAL - LATEROMEDIAL PROJECTION: HAND

Pathology Demonstrated:

• Fractures and/or dislocations of the phalanges, anterior/posterior displaced fractures, and dislocations of the metacarpals are shown. Some pathologic processes, such as osteoporosis and osteoarthritis, also may be demonstrated in the phalanges.

Technical Factor:

• IR size - 18 x 24cm (8 x 10 inches), lengthwise
• Detail screen of digital IR, tabletop
• 55 to 65 kV range
• Accessories - 45degrees foam step support

Compensation Filter:

• May be used to ensure optimum exposure of phalanges and metacarpals due to differences in part thickness.

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:

• Align long axis of hand with long axis of IR.
• Rotate hand and wrist into lateral position with thumb side up.
• Spread fingers and thumb into a "fan" position, and support each digit on radiolucent block as shown. Ensure all  digits, including the thumb, are separated and parallel to IR, and that the metacarpals are not rotated but remain in a lateral position.

Central Ray:

• CR perpendicular to IR, directed to second MCP joint
• Minimum SID of 40 inches (100cm)

Collimation:

• Collimate on four sides to outer margins of  hand and wrist.

Note:

• The "fan" lateral position is the preferred lateral for the hand if phalanges are the area of interest. (see next page for alternative projections.)

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Radiographic Criteria:

Structure shown:

• Entire hand and wrist and about 2.5cm (1inch) of distal forearm are visible.

Position:

• Fingers should appear equally separated, with phalanges in the lateral position and joint spaces open, indicating that fingers were parallel to IR.
• Thumb should appear in a slightly obliqued position completely free of superimposition, with joint spaces open.
• Long axis of hand and wrist should be in a true lateral position, as evidenced by the following: Distal radius and ulna are superimposed; metacarpal are superimposed.

Collimation and CR:

• Collimate should be visible on four sides to area of affected hand.
• CR and center of collimation field should be at second MCP joint.

Exposure Criteria:

• Optimal density and contrast with no motion demonstrate soft tissue margins and clear, sharp bony trabecular markings.
• Outlines of individual metacarpals demonstrated are superimposed.
• Midphalanges and distal phalanges of both thumb and fingers should appear sharp but may be slightly overexposed.