Cervical canal sample averages according to different methods
| TR | SAC (mm) | CDCC (mm) | |
| C3 | 1.02 | 7.15 | 15.95 |
| C4 | 1.00 | 6.56 | 15.52 |
| C5 | 1.01 | 6.41 | 15.54 |
| C6 | 0.94 | 6.23 | 15.51 |
| C3–C6 | 1.00 | 6.59 | 15.63 |
CDCC, corrected diameter of the cervical canal; SAC, space available for the cord; TR, Torg ratio.