Library

The *Qianjin Fang* (Essential Prescriptions Worth a Thousand Gold) states: The method of measuring cun is based on the ancient standard where eight cun constitute one chi. It also specifies taking the first segment of the middle finger (Zhongzhi, 3rd digit) of the male's left hand or the female's right hand as one cun. In cases where finger lengths vary, the transverse width of the first segment of the thumb may be taken as one cun; application requires flexible judgment, with proficiency depending on the practitioner. The *Waitai Miyao* (Secret Essentials of the Outer Cabinet) adopts the same method. Another view holds that three cun equals the total length of one middle finger. The *Taiping Shenghui Fang* (Holy惠民 Formulas of the Taiping Era) states: Currently, the distance between the two inner transverse creases of the second segment of the middle finger of the male's left hand or the female's right hand is taken as one cun. Since adopting this method, many illnesses have been cured. This is now established as the standard for locating acupoints and measuring cun; Shi Zangyong also uses the *Taiping Shenghui Fang* as the benchmark. Using a strip of wax paper or thin bamboo splint, measure the distance between the upper and lower transverse creases of the middle segment of the middle finger of the patient's male left hand or female right hand as one cun; this is called "Tongshen Cun" (Body-Proportion Cun) (If measuring along the side of the bent finger, the distance between the two intersection angles of the upper and lower parts of the middle segment is taken as one cun; if the finger is extended, measure from the lower transverse crease of the proximal phalanx to the center of the middle phalanx, taking the distance between the longer of the two transverse creases as one cun. The measurement of one cun when the finger is bent corresponds to this. However, fingers may vary among individuals, and fingerprints differ; careful consideration is required in these details.) Fold the paper splint to equal six Tongshen Cun, mark each cun with ink, ensuring no variation in length, cut it off, and store it for measuring moxa points. Starting from the depression below the fourth thoracic vertebra at the midline of the spine, measure three cun laterally on each side to locate the Gaohuang (BL43) acupoint, which is where the Qi of the Foot-Taiyang Bladder Meridian emerges.