Fig. 2

C-T section 23 in a is the approximate midpoint through the metatarsal head, at the inter-sesamoidal ridge in our specimen. b illustrates a general circular plane model denoting the distal C-T section 23 in a. Note that normal lines drawn perpendicular to tangential lines define its borders and help establish a CR. These normal lines, due to the geometry of the circle, will always intersect at the circle’s center