The neutral triangle is seen radiologically in-: (A) Neck femur, (B) Proximal humerus, (C) Calcaneum, (D) Talus
Answer is C. Neutral triangle of the calcaneum

Within the trabeculae of calcaneus lies the neutral triangle, an area directly below the distal edge of a posterior facet.
The base of the triangle is the weakest, most vulnerable portion of the calcaneum.
Axial impaction of the talus into the calcaneum results in a vertical fracture through the neutral triangle, and it represents the primary fracture line.