Numerous anatomical observations of the transverse sinus (TS) have been reported and features of this sinus, as assessed by cerebral angiography, are referred to in many monographs. However, there are no studies on the hemodynamics in the TS. We recently investigated the TS, using cerebral angiography with cinematographic films. The subjects were 35 patients who underwent angiography of 3 or 4 vessels at our institute, using Seldinger's method. The contrast material was infused manually. Cinematography permitted observation of the size of the bilateral TS and the direction of blood flow. Depending on the features of the bilateral TS, the patients could be divided into three groups. Type I (cases where the right TS was dominant) accounted for the highest percentage (54.3%, 19/35). In 11 of these 19 cases, the left TS also showed antegrade blood flow. In 6 of the Type I group, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus). In the other two cases rated as Type I, the blood flow through the left TS was in the direction from the Torcular Herophili to the right TS. Fourteen cases (40.0%) were rated as Type II (in which both sinuses were similar in size). In 13 of these 14 cases, blood flow through the bilateral TS was almost symmetrical (Type II-A). In one of the 14 cases, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus).