Objective  To image the veins around the foramen of monro (FM), to build the 3D model of them, to construct venous network in this area and to explore the spatial positional correlation between FM and veins around it.   Methods  Totally 60 healthy subjects were selected to get the original images on 3.0 T MR and procesed the original images by minimum intensity projections (mIP) and Materialise’s interactive medical image control system (Mimics), built the 3D model of the veins around FM, observed and analyzed the morphology of FM and the veins around it on original and processed images. 

  Results  The displaying rate of FM was 65% (78 sides), the displaying rate of internal cerebellar veins (ICV) was 100% (120 sides), the diameter was (2.13±0.30)mm. The displaying rate of anterior septal vein (ASV) was 100% (120 sides), the diameter was(0.69±0.19)mm. The displaying rate of superior thalamostriate vein (STV) was 98.3% (118 sides), the diameter was (1.47±0.38)mm. The displaying rate of superior choroidal vein (SCV) was 82.5% (99 sides), the diameter was(0.40±0.18)mm. According to the relationship between the converging point of the tributaries of ICV and the location of FM, FMs were classified into 5 types:ⅠA, 24.2% (29 sides), ASV converged into ICV at the venous angle and closed to the posterior edge of FM; ⅠB, 13.3% (16 sides), ASV converged into ICV away from the venous angle and the posterior edge of FM; ⅡA, 45% (54 sides), ASV converged into ICV at the false venous angle and closed to the posterior edge of FM; ⅡB, 15.8% (19 sides), ASV converged into ICV away form the false venous angle  and the posterior edge of FM. Ⅲ, 1.7% (2 sides), STV was absent.  Conclusion FM and the veins around it are visible on the susceptibility weighted imaging(SWI). It can be constructed by Mimics that the 3D model of ICV, its tributaries, FM and the converging points of the major veins. The classification of FMs is meaningful to the option of surgical approaches through FM.