Suprapubic punction of the urinary bladder (cystostomy) may cause typical, sometimes lethal injuries of pelvic organs especially in cases of an insufficient bladder filling. Some of these cases were described in the literature of legal medicine. To verify the importance of the cranial displacement of the vulnerable intestine by a filled bladder, the distances between the upper end of the symphysis and apex vesicae were measured in 76 forensic autopsies in situ and correlated with the filling volume of the urinary bladder. 69,2% of cases with a bladder filling volume up to 200 ml showed a suprapubic distance of only < or =4 cm. However, this distance collides with the preferred clinical intervention point, 2 fingers above the symphysis. In all cases with a bladder filling volume > or =300 ml, the distances were > or =5 cm. Based on our measurements, we recommend a preoperative bladder filling of > or =300 ml for an uncomplicated insertion of a suprapubic catheter.