d_rod 3.5[mm] "Rod diameter"
c3_L 11[mm] "C3 screw thread length"
c4_L 12[mm] "C3 screw thread length"
t_angle 10[deg] "Transverse angle"
s_angle 35[deg] "Sagittal angle"
c3_xw 26[mm] "C3 entry coordinate"
c3_yw 1.5[mm] "C3 entry coordinate"
c3_zw 15[mm] "C3 entry coordinate"
c4_xw 38.5[mm] "C4 entry coordinate"
c4_yw 1[mm] "C4 entry coordinate"
c4_zw 16.5[mm] "C4 entry coordinate"