Which tibial sesamoid position corresponds to erosion of the crista from the first metatarsal head?

Which tibial sesamoid position corresponds to erosion of the crista from the first metatarsal head?

• A. 1
• B. 2
• C. 4
• D. 3

Answer: (C)

On a weight-bearing AP foot radiograph, the tibial sesamoid position shows how far the tibial sesamoid has shifted laterally relative to the first metatarsal head. The crista, a plantar ridge on the metatarsal head, is the contact point for the sesamoid. When the tibial sesamoid moves to the most lateral position, it loses stable articulation under the head and presses against the crista, leading to erosion of that ridge over time due to abnormal pressure and friction. Therefore, erosion of the crista occurs with the greatest lateral displacement of the tibial sesamoid. The correct answer is the position representing the farthest lateral shift of the sesamoid.

On a weight-bearing AP foot radiograph, the tibial sesamoid position shows how far the tibial sesamoid has shifted laterally relative to the first metatarsal head. The crista, a plantar ridge on the metatarsal head, is the contact point for the sesamoid. When the tibial sesamoid moves to the most lateral position, it loses stable articulation under the head and presses against the crista, leading to erosion of that ridge over time due to abnormal pressure and friction. Therefore, erosion of the crista occurs with the greatest lateral displacement of the tibial sesamoid. The correct answer is the position representing the farthest lateral shift of the sesamoid.