李志道教授经过50余年临床实践研究，结合解剖学相关知识，发现委中、承山二穴在针刺深度与传统认识有所不同。其中，委中穴在刺入0.5～0.8寸，承山穴在刺入2.0～3.0寸时最易达到循经得气的效果，通过调整针尖方向还可较准确达到气至病所的效果，且针感与相应神经分布区域相吻合。该针感在某些疾病，尤其神经压迫相关症状的治疗中疗效明显，且优于传统教材所述针刺深度。

Professor Li Zhidao, with more than 50 years of clinical practice, inspired by anatomy-related knowledge, found that the needling depth at the two points BL40(Weizhong) and BL57(Chengshan) is different from traditional knowledge. It is the easiest to achieve the effect of qi arrival when needling in 0.5-0.8 cun at point BL40, and 2.0-3.0 cun at point BL57. By adjusting the direction of the needle tip, it can more accurately achieve the effect of qi arrival. The needling sensation is consistent with the corresponding nerve distribution areas. The effect of this acupuncture sensation in the treatment of certain diseases, especially nerve compression related symptoms, is significantly better than that with the needling depth described in traditional textbooks.