Which statement about tangential sesamoid radiography is correct?

• A. The projection is used to visualize calcaneal fractures.
• B. The central ray angle is 15 degrees.
• C. The SID is 40 inches.
• D. The sesamoid bones should be free of superimposition by the first metatarsal.

Answer: (D)

The main idea is to visualize the sesamoid bones clearly by avoiding overlap from the first metatarsal head. In a tangential sesamoid view, the beam is positioned so it runs tangential to the plantar surface at the level of the sesamoids, placing the sesamoids in profile and free from superimposition by the first metatarsal. This separation is what lets you see fractures or other pathology in the sesamoids clearly. The other statements don’t describe the purpose of this projection: it’s not used to assess the calcaneus, there isn’t a fixed 15-degree central-ray angle that defines the view, and while a typical foot radiograph uses a standard distance, the critical feature of this view is avoiding overlap with the first metatarsal.