The course of the Bladder Channel of Foot-Taiyang on the body surface was observed with low frequency sound wave (LFSW) in 40 healthy adults. The results shows in the following: (1) When LFSW was given at Zhiyin (BL67) point, the occurrence rate of conducted wave (ORCW) of various inspected points on the superficial course of the Bladder Channel varied from 60.0% to 95.0%, and their amplitudes were markedly higher than those of control points on both sides of the channel (P<0.01). It is indicated that tracks of LFSW are consistent with the course of the Bladder Channel described in TCM; (2) On the first lateral line and the second lateral line of the Bladder Channel, the ORCW of the middle point between Dazhu (GV14) and Fufen (BL41) points was significantly lower than at of the two points at the same level. It suggested that the two branches of the Bladder Channel at the back originate from Tianzhu (GV14); (3) The three points, i.e. the middle point between Yinmen (BL37) and Weizhong (BL40), the point of the external line at the same level, and the middle point between Yinmen and Weiyang (BL39) were observed. results indicated that ORCW of the points of medial line and lateral line were 85.0% and 87.5% respectively, significantly higher than that of the middle point between Yinmen (BL37) and Weizhong (BL40) (P<0.01). It shows that the two branches do not cross and they are parallel each other; (4) When LFSW was applied to Zhiyin, Jinmen (BL63), ORCW of the middle point between Jinmen and Pucan (PL61), Pucan, and Shenmai (BL62) were investigated at the same time. The results indicated that ORCW of the first three points are significantly higher than that of the last one (P<0.01), and LFSW did not convey along the course from Jinmen to Shenmai (BL62), but from Jinmen (BL63) to Pucan directly. In order to find the relationship between Shenmai and the Gallbladder Channel, LFSW was applied to Qiaoyin point and found that the ORCW rate at Shenmai was significantly lower than that of Qiuxu (GB40). Therefore, the authors hold that the traditional location of Shen-mai probably is wrong; (5) When LFSW was applied to Canzhu (BL2), the ORCW of Tinggong (SI19) (82.5%) was significantly higher than those Ermen (Th21) (5.0%) and Tinghui (GB2) (7.5%) (P<0.01), suggesting that the Bladder Channel and the Small Intestine Channel link each other; (6) When LFSW was applied to Zhiyin (BL67), the sound wave amplitudes at Jinmen (BL63), Kunlun (BL60), Chengshan (BL57) and Yinmen (BL37) were significantly higher than those of the same four acupoints when LFSW was given to Zhijing (P<0.01), indicating that LFSW has the property of conveying sound waves along the channel.

By Wei Tianshu, Xu Bo Lin Liquan & Sun Pingsheng