The aspect ratio for tetrahedrons is defined using four boundary triangles and six mid triangles. The mid triangles are formed connecting the corner nodes to the shortest distance point of the adjoining edges.

Tetrahedron Aspect Ratio is defined as the maximum aspect ratio of ten triangles, four boundary triangles and six projected triangles. Here the boundary triangles are (0,1,2), (0,1,3), (0,2,3), (1,2,3). The projected triangles formed by connecting the corner angles to the shortest distance point of the adjoining edges are (0,1,5), (1,2,3), (2,5,1), (0,1,2), (0,2,1), (1,5,2).