Question

The inter phalange always joints should appear open on posteroanterior hand images. Name two positioning criteria to accomplish opening these joints

Answer 1

The Hand PA view is part of a two view series metacarpals, phalanges, carpal bones and distal radial ulnar joint.

Patient position

• patient should be seated alongside the table
• Affected arm is flexed at 90° so that arm and hand can rest on the table
• Affected hand is placed, palm down on the image receptor
• Shoulder, elbow, and wrist should all be in the transverse plane, perpendicular to the central beam
• Hand and elbow should be at shoulder height which makes radius and ulna parallel.

TECHNICAL FACTORS:

Posteroanterior projection:

Centering point: third metacarpal head

Collimation:

• laterally to the skin margins
• proximal to include distal radioulnar joint
• distal to the tips of the distal phalanges

Orientation: portrait

Detector size: 18 cm x 24 cm

Exposure:

• 50-60 kVp
• 1-5 mAs

SID: 100 cm

Grid: no

Image technical evaluation:

• 5th finger is positioned PA, with no rotation as evidenced by the symmetric appearance of the concavities of the phalanges.
• Interphalangeal and metacarpophalangeal joint spaces of digits 2 to 5 should appear open.
• Concavity of metacarpal shafts should be equal .

Practical points:

• The hand is not a technically challenging radiograph.
• Ensure the fingers are in equal distance apart
• Detector is high enough to avoid overlap at the wrist.
• Include the wrist joint on your PA radiograph, patients may have pain from pathology other than the hand.

Figure 1: Right hand PA view

Figure 2: Left hand PA view