Fig 3. Discriminant Function Plot for all included regions (proximal and distal ends of the middle and proximal phalanges and the metacarpal head).

Along Function 1, knuckle walkers have high BV/TV in the proximal and distal ends of the proximal phalanges and proximal end of the middle phalanges and more palmar-dorsal alignment in the metacarpal head and distal end of the proximal phalanges. Quadrupeds and suspensory primates have more proximo-distal alignment in those regions.