Fig. 4

a Tapering angle of the Med and Lat of the cortex. Significant differences were observed between the Med and Lat, except at the 20 mm level. *Lat indicates statistical significance at each resection level. n.s., not significant; Med, most medial point; Lat, most lateral point. b Tapering angle of the QMA, CA, and QLA. The tapering angle of the QMA was positive at all levels, whereas that of the QLA was negative. n.s., not significant; QMA, quarter-medial-anterior point; CA, central-anterior point; QLA, quarter-lateral-anterior point. c Tapering angle of the QMP, CP, and QLP. The tapering angle of the QMP and QLP increased with the more distal resection level in which significant differences were observed between QMP and QLP, except at the 5 mm level. *CP indicates statistical significance at each resection level. n.s., not significant; QMP, quarter-medial-posterior point; CP, central-posterior point; QLP, quarter-lateral-posterior point