Foot AP Axial is a radiography positioning projection of the Lower Extremity. Foot dorsiflexed on IR, CR angled 10° cephalad toward heel. SID 40". The centering point is located base of the 3rd metatarsal, with foot dorsiflexed on ir.. The central ray is angled 10 degrees cephalad toward the heel, perpendicular to the long axis of the foot.. Image-quality criteria include entire foot including tarsals and metatarsals visible without superimposition., tarsometatarsal joints opened by the cephalad cr angulation.. Standard exposure ranges from 60 to 70 kVp, 3 to 6 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- All five metatarsals without overlap.
- Metatarsal bases and articular facets.
- Tarsometatarsal joints open and clear.
- Talar head and navicular bone.
- Cuboid and cuneiform bones.
- Plantar surface of the foot without superimposition.
Patient preparation
- Verify patient identity using two identifiers.
- Remove footwear, socks, and any radiopaque foot jewelry.
- Position the patient supine or seated with the leg extended.
- Place the affected foot flat on the IR.
- Dorsiflexe the foot by pulling the toes toward the shin.
Position & centering point
Base of the 3rd metatarsal, with foot dorsiflexed on IR.
Central ray
Angled 10 degrees cephalad toward the heel, perpendicular to the long axis of the foot.
Exposure / technique
- kVp
- 60–70
- mAs
- 3–6
- SID
- 40" (102 cm)
- Notes
- CR angled 10 degrees cephalad to open the tarsometatarsal joints.
Image-quality criteria
- Entire foot including tarsals and metatarsals visible without superimposition.
- Tarsometatarsal joints opened by the cephalad CR angulation.
- Talar head and navicular bone clearly demonstrated.
- Metatarsal heads aligned in a straight line without overlap.
- Bone trabeculae sharp, no motion artifact.
- Collimation: 1 inch on all sides of foot, 1 inch beyond calcaneous shadows.
Common errors / ARRT traps
- 1 Insufficient CR angulation (less than 10 degrees) fails to open tarsometatarsal joints.
- 2 Failure to dorsiflexe the foot closes the tarsometatarsal articulations.
- 3 Centering off the mid-foot clips the heel from the collimation field.
- 4 Plantar flexion instead of dorsiflexion superimposes tarsal structures.
Clinical indications
- Evaluation of tarsal alignment or dislocation.
- Suspected fracture of the midfoot or tarsals.
- Assessment of flat foot or pes planus deformity.
Aligned to the 2025 ARRT Content Specifications.