This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
The neutral triangle is seen radiologically in- 
Select and explain. 
A. Neck femur, B. Proximal humerus, C. Calcaneum, D. Talus
C: Calcaneum
Answer: C: Calcaneum 
Explanation: 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.