Background: Superficial anastomotic veins (SAVs) have been Studied extensively but little attention has been paid to clinical studies. The aim of this Study is to provide variations in the drainage patterns of SAVs depending on the intraoperative findings. Methods: A total of 25 1 craniotomies due to intractable temporal lobe epilepsy were performed between 1972 and 1987 at the Montreal Neurological Institute. The courses of the three largest SAVs including the vein of Trolard (VT), vein of Labbe (VL) and Superficial Sylvian vein (SSV) were Studied. Results: All three veins showed variable Courses. The most common predominant vein was the combination of the VL + SSV. The VT and VL were frequently coursed at the level of the central vein and middle temporal vein, respectively. On the right hemisphere the SSV was the predominant type while the VL tended to be predominant oil the left hemisphere. A combination of VL and SSV was predominant in patients with right and/or left hemispheric dominance. Conclusions: The SAVs showed considerable variation in their courses and it is difficult to define an exact pattern although some courses showed constant directions. Attention should be paid not to damage these veins since in a considerable number of cases it single dominant vein may be responsible for draining, a majority of the lateral surface of cerebral hemisphere.