When positioning the patient for a plantodorsal (axial) projection of the calcaneus, how should the foot be positioned?

For a plantodorsal (axial) projection of the calcaneus, the foot should be positioned in dorsiflexion. This positioning is crucial because it helps to improve the visualization of the calcaneus by directing the x-ray beam perpendicularly to the long axis of the foot and targeting the subtalar joint.

When the foot is dorsiflexed, the angle allows the x-ray beam to adequately penetrate through the calcaneus while minimizing superimposition from other structures in the foot. This positioning also aids in demonstrating the talocalcaneal joint space clearly. Additionally, the viewer can see the profile of the heel without obstruction, which is vital for assessing fractures or other pathologies in this region.

In contrast, if the foot is positioned in plantarflexion or supination, it would not provide the necessary alignment for an optimal radiographic image of the calcaneus. A neutral position, while potentially adequate, does not enhance the clarity of the image as effectively as dorsiflexion does. Thus, dorsiflexion is the ideal choice for obtaining a proper plantodorsal projection of the calcaneus.