Poor visualization and restricted access often make tumor lesions in the lower rectum difficult to excise, particularly in a narrow male pelvis. The aim of this study was therefore to study whether (and if so to what extent) different positions of the patient on the operating table might improve accessibility. Twenty consecutive patients (men and women) undergoing laparotomy with surgery of the lower rectum were studied. The geometric configuration of the pelvis was studied and compared on lateral radiographs obtained at the operating table in each of four positions. Compared with the conventional lithotomy position, "the thighs-flat" position caused significant extension movement of the lumbosacral joint. Augmentation of the lumbar lordosis widened the pelvic view and enabled a more vertical view of the lower rectum (27.5 degrees in lithotomy position, 13.0 degrees in the thighs-flat position). Insertion of a "lumbar pad" contributed further to the augmentation (7 degrees). When compared on radiographic studies, the thighs-flat position is preferable to the conventional lithotomy position in terms of facilitating low rectal surgery by improving both visibility and accessibility to the pelvic cavity.