An Exploration of the Needling Depth in Acupuncture: The Safe Needling Depth and the Needling Depth of Clinical Efficacy

Table 4

Summary of researches using ultrasound images for measurement of the depths of acupuncture points.

Authors and year	Subjects and sample size	Investigated acupuncture points and their body regions/meridians	Parameters used in comparison and related factors	Results, suggestions, and conclusions
Lian 1995 [79]	89 adults	From BL11 to BL21 (11 points)	Gender, age, BL, BW, disease type, side, and AW	(1) Depths ranged 12–40 mm; (2) Depth was not affected by age or body sizes; (3) Points of male subjects and right side of the body had greater depths; (4) Disease type did not affect depth; (5) Depths measured were shorter compared to ancient writings
Streitberger et al. 2007 [25]	50 patients receiving acupuncture including PC6 bilaterally (97 wrists)	PC6	Nerve penetrated or contacted DQ	(1) Association between nerve contact and de-qi was discussed. De-qi was elicited in 85 cases. No association between the number of nerve contacts and de-qi was found; (2) The mean distance from the needle tip to the nerve was 1.8 mm (standard deviation 2.2; range 0–11.3). Nerve contacts were recorded in 52 cases, in 14 of which the nerve was penetrated by the needle