Toes AP is a radiography positioning projection of the Lower Extremity. Foot flat on IR, CR 10-15 degrees toward the heel to the MTP joint in question. SID 40". The centering point is located MTP joint in question (Bontrager) or 3rd MTP joint (Merrill's), with foot flat on IR. The central ray is 10-15 degrees toward the heel, perpendicular to the phalanges, centered to the MTP joint in question; or perpendicular with a 15-degree wedge under the forefoot. Image-quality criteria include all five toes visible and included in the collimation field, no rotation: phalanx and distal metatarsal shafts equally concave on both sides. A sample technique is 63 kVp with DR 0.9 or CR 2 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- All five toes from the tips to the distal metatarsals.
- Metatarsophalangeal and interphalangeal joints open.
- Sesamoids, if present, may show through the first metatarsal head.
- Distal metatarsals and the metatarsophalangeal joints.
Patient preparation
- WARNING: with possible spinal injury or severe trauma, do not attempt to move the patient; do not rotate a severely injured part or remove splints (Bontrager). Merrill's: do not attempt true AP or lateral positioning of a severely injured limb; take two projections 90 degrees apart, moving it as little as possible, and move the IR and tube if the patient cannot reach the position.
- Verify patient identity using two identifiers.
- Remove footwear, socks, and any radiopaque foot jewelry.
- Position the patient supine or seated with the knee flexed.
- Place the affected foot flat (plantar surface) on the IR.
- Align the foot so the toes lie flat on the IR.
Position & centering point
MTP joint in question (Bontrager) or 3rd MTP joint (Merrill's), with foot flat on IR.
Central ray
10-15 degrees toward the heel, perpendicular to the phalanges, centered to the MTP joint in question; or perpendicular with a 15-degree wedge under the forefoot.
Exposure / technique
- kVp
- 63
- mAs
- DR 0.9 / CR 2
- SID
- 40" (102 cm)
- Notes
- Tabletop technique. All five toes must be visible in the collimation field. Sample technique: DR 0.9 / CR 2 mAs at 63 kVp, 40 in SID, for a 1.5 cm part. Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- All five toes visible and included in the collimation field.
- No rotation: phalanx and distal metatarsal shafts equally concave on both sides.
- Interphalangeal and metatarsophalangeal joints visible and open.
- At least the distal half of the metatarsals included.
- Bone trabeculae sharp, no motion artifact.
- Collimation: 1 inch on all sides of toes.
Common errors
- 1 Patient rotating the foot inward or outward creates oblique projection.
- 2 CR not centered to the MTP joint in question (Bontrager) or the 3rd MTP (Merrill's).
- 3 A perpendicular CR without a wedge, or too little forefoot elevation, closes the IP and MTP joints.
Clinical indications
- Trauma evaluation for suspected toe fracture or dislocation.
- Pathologies such as osteoarthritis and gout, especially in the first digit.