Frequency of each type of cerebral venous variation in the region of the third ventricle
| Type | ASV-ICV Junction | Type of Venous Angle | |
|---|---|---|---|
| IA | 407 (63.4%) | Foramen of Monro | Venous angle |
| IB | 111 (17.3%) | Beyond foramen of Monro | Venous angle |
| IIA | 106 (16.5%) | Beyond foramen of Monro | False venous angle |
| IIB | 17 (2.6%) | Beyond foramen of Monro | False venous angle |
| III | 1 (0.2%) | Beyond foramen of Monro | Venous angle |
Note:—ASV-ICV indicates anterior septal vein-internal cerebral vein.