Anatomy of the Torcular Herophili
| Both Transverse Sinuses Normal Caliber | One Transverse Sinus Absent or Hypoplastic | Both Transverse Sinuses Absent | |
|---|---|---|---|
| Occipital sinus absent (n = 41) | 20 | 21 (18 hypoplasia, 3 absent) | 0 |
| Occipital sinus present (n = 9) | 3 | 5 (2 hypoplasia, 3 absent) | 1 |