BACKGROUND:Knowledge of retropedtoneal space communications might influence catheter placement,and understanding the normal anatomy of the retroperitoneal space is a prerequisite for predicting the distribution of inflammation or other fluid collections in this region. Until recent years,the media/ attachment of the posterior renal fascia remained controversial. The multiple detector spiral CT can show the abdominal anatomic details. So,using the multiple-detector spiral CT to study the anatomy of posterior renal fascia has clinical significance. OBJECTIVE:To describe the medial attachment of the posterior renal fascia by using multiple-detector spiral CT. DESIGN,TIME AND SETTING:A retrospective case analysis was performed at Department of Radiology,Affiliated Hospital of Weifang Medical College between June 2003 and November 2007. PARTICIPANTS:A total of 52 patients with retropedtoneal inflammatory diseases were retrospectively reviewed through analysis of their CT data. METHODS:Toshiba Akuilion 16-detector spiral CT was employed for scanning. Of the 52 patients,15 were proved by clinical and laboratory findings and 37 were proved by surgery and pathology. Among the 52 patients,17 suffered from appendicitis,1 from ureteritis,2 from abscesses in the perirenal space,3 from abscesses in the posterior pararenal space,and 29 from pancreatltis. MAIN OUTCOME MEASURES:Medial attachment of the bilateral posterior renal fascia. RESULTS:At the level of the upper pole of kidney,the posterior renal fascia fused with the fascia of the ipsilateral quadratus lumborum muscle. Forty-six patients manifested the attachment site of the left posterior renal fascia transforming from the quadratus lumborum muscle fasciae to the psoas major muscle fascia at the level of the lower pole of kidney or the infrarenal space. Fifty patients showed the attachment site of the right posterior renal fascia transforming from the quadratus lumborum muscle fascia to the psoas major muscle fascia at the level of the lower pole of kidney or the infrarenal space. CONCLUSION:The posterior renal fascia attachment site is not the same all the time. At different levels,the attachment site of the posterior renal fascia is distinct.