| Name of Projection | Foot - Dorsiplantar (DP) |
| Area Covered | Phalanges, metatarsals, navicular, cuneiforms and cuboid |
| Pathology Shown | Fractures, dislocation, foreign body, joint space abnormalities |
| Radiographic Anatomy | Foot Radiographic Anatomy |
| IR Size & Orientation | 24 x 30 cm
Portrait, divided in two can usually fit 2 views, use lead masking for unused area |
| Film / Screen Combination | Detail
(CR and DR as recommended by manufacturer) |
| Bucky / Grid | No |
| Filter | Yes - when using film a thin filter covering phalanges and distal metatarsals |
| Exposure | 55 kVp
3.2 mAs |
| FFD | 100cm |
| Central Ray | Centre to include foot
Directed at base of 3rd metatarsal
- 10°posteriorly (towards the heel)
- 5° posteriorly for a low arch
- 15° posteriorly for a high arch
|
| Collimation | Outer skin margins of foot on four sides |
| Markers | Distal and Lateral
Marker orientation AP |
| Shielding | Gonadal (check your department's policy guidelines) |
| Respiration | Not applicable |
| Positioning | - Patient supineon the X-ray table or barouche
- Flex the knee of the affected leg
- Place IR under foot parallel to its long axis
- Place plantar surface of the foot flat to IR
- Centre to the base of 3rd metatarsal
|
Critique
| Positioning
- No rotation is evidenced by
- The joint between the medial and intermediate cuneiformsis open (this is closed when the foot is rotated)
- First metatarsal shaft has equal concavity on both sides
- Nearly equal spacing between 2nd to 5th metatarsals
- There should be overlap of 2nd to 5th metatarsal bases.
- In the DP Axial projection, the tarso-metatarsal and navicular-cuneiform joint spaces will be open
Area Covered
- Proximal calcaneus, talar neck, tarsals (navicular, cuneiforms and cuboid), metatarsals, phalanges and surrounding foot soft tissue are included
Collimation
- Centre: The base of the third metatarsal
- Shutter A: Open to include the outer skin margins of the lateral and medial sides of the foot
- Shutter B: Open to include the soft tissue of the toes and the proximal calcaneus
Exposure
- Bony trabecular patterns and cortical outlines are sharply defined
- Soft tissues are visualised
- Correct use of a filter will give uniform density of phalanges and metatarsals
|
| Special Notes | Effect of lateral rotation
- Navicular tuberosity is shown in profile
- There is an increase in the superimposition of the metatarsal bases
Effect of medial rotation
- There is an decrease in the superimposition of the metatarsal bases
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