Fingers Projections
Patient Preparation
- Explain the procedure to the patient.
- Remove rings, jewelry, or metallic objects from the hand.
- Position the hand comfortably on the image receptor (IR).
- Use lead shielding as appropriate.
BASIC PROJECTIONS
1. Posteroanterior (PA) Projection — Finger
Positioning:
- Patient seated at the table.
- Hand pronated and palm down on the IR.
- Finger of interest fully extended and separated from adjacent fingers.
- Center finger to the IR.
Central Ray (CR):
- Perpendicular to IR.
- Directed to the proximal interphalangeal (PIP) joint of the finger of interest.
SID (Source-to-Image Distance):
- 100–110 cm (40–44 inches).
Collimation:
- Include distal phalanx to distal metacarpal of the finger.
Evaluation Criteria:
- Phalanges visualized with minimal distortion.
- Open interphalangeal and metacarpophalangeal joints.
- Soft tissue detail visible.
2. PA Oblique Projection — Finger
Positioning:
- Hand pronated on the IR.
- Finger of interest rotated 45° laterally (for radial side fingers) or medially (for ulnar side fingers).
- Adjacent fingers separated.
Central Ray (CR):
- Perpendicular to IR.
- Directed to the PIP joint of the finger of interest.
SID:
- 100–110 cm (40–44 inches).
Collimation:
- Include distal phalanx to distal metacarpal.
Evaluation Criteria:
- Phalanges visualized with oblique separation of overlapping structures.
- Interphalangeal joints open.
- Soft tissue margins clear.
OTHER PROJECTIONS
3. Lateral Projections — Finger (Mediolateral and Lateromedial)
Positioning (Mediolateral):
- Hand in true lateral with the finger of interest extended.
- Finger positioned on the side closest to the IR (radial or ulnar depending on digit).
- Adjacent fingers flexed or out of field.
Positioning (Lateromedial):
- Finger placed lateral side away from IR.
- Other fingers flexed or separated.
Central Ray (CR):
- Perpendicular to IR.
- Directed to the PIP joint of the finger of interest.
SID:
- 100–110 cm (40–44 inches).
Collimation:
- Include distal phalanx to distal metacarpal.
Evaluation Criteria:
- Phalanges in true lateral position.
- Fingernail in profile.
- Open interphalangeal and metacarpophalangeal joints.
- No rotation or motion.
Image Evaluation Checklist
- Entire phalanges visualized.
- Correct exposure and sharpness.
- Proper lateral or oblique rotation.
- Anatomical markers correctly placed.
- SID maintained at 100–110 cm.
Common Pathologies Demonstrated
- Fractures of distal, middle, or proximal phalanges.
- Dislocations of interphalangeal joints.
- Osteoarthritis or degenerative changes.
- Soft tissue swelling or foreign bodies.