<prompt> The neutral triangle is seen radiologically in-Neck femurProximal humerusCalcaneumTalus  <response>: Neutral triangle of the calcaneumWithin 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. 