Objective To observe the variation of sacral vertebrates and foramen involving the bilateral Shangliao(BL 31)

Ciliao(BL 32)

Zhongliao(BL 33)and Xialiao(BL 34

Baliao acupoints)

so as to provide an anatomic basis of acupoint needling in clinical practice.Methods A total of 290patients[161men and 129 women

mean age and standard deviation

(63.6±13.3)years old and(59.5±13.3)years old

respectively]with intact pelvic structure were recruited in the present study.Computed tomography(CT)scans of intact pelves were taken using a SOMATOM Definition AS 128 and the acquired signals were imported into Siemens Syngo Inspace platform for 3Dreconstruction

followed by identification

classification and analysis of the variation of sacral foramen(Baliao acupoint).Results The total variation rate of posterior sacral foramen(Baliao acupoint)was 20.34%(59/290).The detected three types of variation were sacral vertebrae number variation(4sacral vertebraes

6sacral vertebraes)

fusion variant(lumbosacral fusion

sacrococcygeal fusion

lumbosacral & sacrococcygeal fusion

and lumbosacral fusion & S 4variation)and mixed type.Conclusion Variations of sacral vertebrae including the number and fusion exist in the human body

suggesting an increase of the difficulty of acupoint needling.Since posterior iliac spine does not change generally

it is recommended to be used as a reference point for locating the Baliao acupoint.