There is one valuable and important tip in point selection and that is the “concentration”. When select points from different channels, one must pay attention to the restraining or attacking relations between or among channels. Sciatica usually involves with three channels: lateral (Shao Yang wood), posterior (Tai Yang water), and anterior (Yang Ming earth). If all three channels are needled at the same time, restraining between channels will occur: wood restrains earth; and earth restrains water. The result is far less effective than only needle on Bladder channel or Gall Bladder channel. Since the Daoma of Linggu and Dabai only apply one channel, the result is concentrated and strong.
Linggu and Dabai are located on the lateral side of the second metacarpal bone. From the perspective of holographic theory, Linggu corresponds to lower jiao and lumbar and legs in the upright direction of the second metacarpal bone to the whole body; Dabai corresponds to lower jiao and lumbar and leg in the reversed direction. Both points can treat lumbar and legs (including sciatica). When they are used together to treat lower jiao, lumbar and leg, the effectiveness is certainly strong.
From the perspective of the hand-trunk correspondence, fingers correspond to the genital area, palm corresponds to hip area and lower back and hence points of this area treat sciatica. Besides, from the perspective of hand-foot reversed correspondence, hand also corresponds to the hip area and hence treats sciatica. Both correspondences indicate the treatment of sciatica. Hence, Linggu and Dabai, the two points on hand, treat sciatica with superb effectiveness.
Both of the insertions of Linggu and Dabai are along and close to the bone. The technique matches the saying in Lingshu, chapter 7 Guanzhen: ““The so-called Duan Ci is to treat bone bi-syndrome. After the insertion, wave the needle slightly to advance the needle and cause the tip of the needle to approach the bone; and apply lifting and thrusting method to rub the bone.” This is similar to the “using bone to treat bone” technique in the Ti Ying (body correspondence) needling methods. The insertion is effective in treating bone pain including sciatica.
From the perspective of the “using body (tissues) to treat (disease) images” in the Ti Ying needling methods: through the extraordinary connection of the large intestine channel and liver channel (belongs to wood), large intestine also corresponds to wood and treat tendon diseases; the element of Dabai point is also wood and hence treats tendon related diseases. Since both points are close to the bone; and as “using bone to treat bone”, both points treat tendon and bone (wood and water) simultaneously. The sciatica is usually related to water (bladder channel) and wood (gall bladder channel). Or it belongs to the liver channel if the pain is at groin, both points can still treat it through the extraordinary connection of the large intestine and liver. If the pain falls in the yangming channel, through the communications of the same name hand and foot channels, these two points also can treat.
As far as the question of why the result is not good, it is mostly caused by improper technique. The needling depth plays an essential role in the treatment: shallow depth or heaven division treats local diseases or diseases close to the needling point; medium depth or human division treats diseases located farther to the needling point; and deep depth or earth division treats diseases even farther. Using points located in the upper body to treat the diseases located in the lower, it is necessary to needle deep enough to gain effect. (Also see the previous discussion questions for more details.) Linggu and Dabai both points must be needled to the earth division (average 1.5 cun to 2.0 above) to gain good result. If the needling depth is not deep enough, the result is certainly not good. Besides, if the Dongqi (activating qi) technique (asking the patient to exercise the disorder site) is not incorporated, the result is even less effective. If the needling depth is not deep enough, the righteous qi can not be regulated. It is said that the local, shallow or heaven division needling is to drain the pathogens residing in yang division/layer; medium or human division needling is to drain the pathogens residing in yin division; and earth division needling is to strengthen the grain qi or righteous qi. The sciatica pain mostly is chronic, prolonged and cold nature. To gain a lasting effect, the needle must reach to the earth division and long retained to strengthen the grain qi and righteous qi. If the needling depth is not deep enough or the needle retention is not long enough, the treatment effect is neither prominent nor lasting.