Variations of dural sac shape as seen on macroscopic photographs of 70 dissected adult lumbar spine segments
| Lumbar Level | Polygonal (hexagonal, pentagonal, or square) Shape | Triangular or Y Shape |
|---|---|---|
| L1 | 79 | 21 |
| L2 | 79 | 21 |
| L3 | 57 | 43 |
| L4 | 57 | 43 |
| L5 | 64 | 36 |
Note.—Data are percentages.