Objective To determine the location of Ciliao (BL 32) by the help of three-dimensional (3-D) surface reconstruction of computed tomography (CT) so as to provide a reference for clinical application. Methods A total of 106 female volunteer subjects were enrolled in the present study. A CT scanner was used to scan the subjects' pelvis

and the collected image data was processed by Dextroscope workstation. The distances and angels of Ciliao(BL 32) in the 3-D space were measured. Results A linear correlation existed between the inter-iliac distance (L 1) and sacro-foremen distance (L 2

with the regression equation being Y=20.219+0.25X)

and between the sacro-iliac distance and sacral foremen-iliac distance (with the regression equation being Y=-14.007+0.446X)

which were used to determine the location of BL 32. A linear correlation also existed between the body weight and the needling depth (with the regression equation being Y=-18.893+0.988X). So

the suitably inserted straight depth of acupuncture needle could be determined according to the woman's body weight.The oblique angle of the 2 nd sacral foremen was (30.08±4.26)°

and the depth of the 2 nd sacral foramen was (20.13±2.11) mm. Conclusion In accordance with the results obtained from CT 3-D reconstruction

oblique needling of an acupuncture needle for Ciliao (BL 32) is highly recommended.