How should the image receptor be positioned for a calcaneal axial radiograph?

How should the image receptor be positioned for a calcaneal axial radiograph?

• A. Image receptor centered to ankle with plantar foot perpendicular to it
• B. Image receptor placed under knee
• C. Image receptor oriented medially
• D. Image receptor at 90 degrees to plantar surface

Answer: (A)

For an axial calcaneus radiograph, align the image receptor with the ankle and keep the plantar surface of the foot perpendicular to the receptor. Centering the receptor to the ankle ensures the calcaneus is well positioned within the image field, while having the plantar surface perpendicular to the receptor prevents tilt that could distort the calcaneus in the axial view. This setup allows the central ray, typically angled cephalad, to pass through the calcaneus along its axis, producing a clear projection of the calcaneal tuberosity, sustentaculum tali, and subtalar joint without excessive foreshortening or superimposition.

Placing the receptor under the knee would miss the calcaneus, orienting the receptor medially would rotate the foot out of true alignment, and placing the receptor at 90 degrees to the plantar surface would misorient the image planes.