| Name of projection | Foot - Oblique (Medial Rotation) |
| Area Covered | Entire foot from distal phalanges to the calcaneus, and the talus |
| Pathology Shown | Fractures, dislocation, foreign body, joint space abnormalities |
| Radiographic Anatomy | Foot Radiographic Anatomy |
| IR Size & Orientation | 24 x 30cm
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 | 57 kVp
3.2 mAs |
| FFD / SID | 100cm |
| Central Ray | Directed at base of the 3rd metatarsal
Perpendicular to the IR |
| Collimation | Outer skin margins of the foot on four sides |
| Markers | Distal and Lateral
marker orientation AP |
| Shielding | Gonadal (check your department's policy guidelines) |
| Respiration | Not applicable |
| Positioning | - Patient supine supineon the X-ray table or barouche
- Flex the knee of the affected leg
- Place IR under foot parallel to its long axis
- Internally (medially) rotate the leg until the plantar surface is at a 45° angle to the IR (refer to Special Notes below)
- Use a sponge for stabilising the foot in this position
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Critique
| Positioning
- The correct obliquity is evidenced by
- the 1st and 2nd metatarsals should only be superimposed at the bases
- 3rd through 5th metatarsals should not be superimposed
- base of the 5th metatarsal (tuberosity) should be well shown
- the tarsal sinus is well shown
- joint spaces around the cuboid are open
- the cuboid is seen in profile
Area Covered
- The entire foot should be demonstrated to show all phalanges, metatarsals, calcaneum and proximal talus
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
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| Special Notes | Effect of over rotation
- the base of the 5th metatarsal is superimposed over the tubercle of the 4th metatarsal
- the joint space between the 4th and 5th metatarsals is closed
Effect of under rotation
- the base of the 4th metatarsal is superimposed over the base of the 5th metatarsal
- the joint space between the 4th and 5th metatarsals is closed
Angle of obliquity
- This angle will vary according to the arch of the foot.
- 45° for a normal arch
- 30° for a low arch
- 60° for a high arch
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