Where is the central ray entered for a calcaneal axial radiograph?

Where is the central ray entered for a calcaneal axial radiograph?

• A. Enter midline at base of 3rd metatarsal
• B. Enter at navicular
• C. Enter at plantar aspect of heel
• D. Enter at posterior calcaneus

Answer: (A)

The axial view of the calcaneus is done with the central ray directed along the long axis of the calcaneus, typically with a cephalad angle. Entering the beam at the midline on the plantar aspect over the base of the third metatarsal places the ray in the correct path to travel through the calcaneus and exit near its posterior aspect, giving a true axial projection that opens the subtalar joint and clearly shows the calcaneal tuberosity. This precise entry point ensures consistent alignment and minimizes distortion or superimposition of adjacent structures. Entering at other locations, such as the navicular region or posterior calcaneus, would misalign the ray and degrade the diagnostic view, and aiming at the plantar heel without the midline alignment wouldn’t place the beam along the calcaneus axis for this projection.

The axial view of the calcaneus is done with the central ray directed along the long axis of the calcaneus, typically with a cephalad angle. Entering the beam at the midline on the plantar aspect over the base of the third metatarsal places the ray in the correct path to travel through the calcaneus and exit near its posterior aspect, giving a true axial projection that opens the subtalar joint and clearly shows the calcaneal tuberosity. This precise entry point ensures consistent alignment and minimizes distortion or superimposition of adjacent structures. Entering at other locations, such as the navicular region or posterior calcaneus, would misalign the ray and degrade the diagnostic view, and aiming at the plantar heel without the midline alignment wouldn’t place the beam along the calcaneus axis for this projection.