For tangential sesamoid radiography, which is a valid patient position?

• A. Standing
• B. Lying supine
• C. Prone
• D. Seated on the radiographic table

Answer: (B)

The key idea is to visualize the small sesamoid bones by getting the x-ray beam to skim tangentially along the plantar surface of the first MTP joint. This requires positioning the foot so the plantar aspect is nearly parallel to the image receptor and the toes can be dorsiflexed to place the sesamoids in profile with minimal overlap.

Lying supine provides a stable, non-weight-bearing setup that makes it easier to dorsiflex the toes and hold the foot in the precise position needed for a true tangential view. The beam can then be angled to run tangent to the plantar surface, producing a clean image of the sesamoids without distortion from weight-bearing or motion. Standing or seated positions introduce weight-bearing forces and less reliable control of the required plantar flexion angle, while prone isn’t necessary if a supine arrangement already achieves the tangential alignment.