Fig. 4

The relative position of the ankle canal reference line l and the medial and lateral nerve: a a schematic diagram showing two projection lines,P1 is projection of the lowest point of the medial malleolus and P2 is projection of the calcaneal tuberosity on the sagittal image; b the relative position of the bifurcation point and Line 1 and Line 2 on the sagittal image through the bifurcation point of the medial and lateral nerves of the plantar; c measure the distance between the bifurcation point and P1 and the angle between the bifurcation point and Line 1 on the sagittal image passing through the bifurcation points of the plantar and lateral nerves