Medical Dialogue
医学会话
Discussion on Point Location
讨论针灸穴位
It is in the student clinic at the White Mountain School of TCM in the USA, where Dr. Paul Conner, a clinical supervisor, and second-year students are discussing the location of stomach 36 (ST36, zusanli) in Grand Rounds, following the clinic shift.
| doctor: | Welcome to this afternoon Grand Rounds. |
| student: | Good afternoon, Dr. Connor. And thank you for guiding us as we learn. |
| doctor: | You are welcome. And since you are still learning, I think we need to clarify the location of ST36? |
| student: | In my studies, I remember ST36 as being 3 cun below stomach 35 (ST35), one finger width from the anterior aspect of the tibial crest, in the muscle called tibialis anterior. |
| doctor: | Sounds like you've memorized one of our textbooks. You have a good memory. Can you explain what a "cun" is, and how we use it to find that point? |
| student: | I hope my memory is as good as you think! It is use proportional measurement in finding points. In the specific case of ST36, we need to know the distance from the popliteal crease to the tip of the lateral malleolus. That distance is 16 cun. Yes, and we call it proportional measurement because no matter how long a person's leg may be, it is "proportionally 16 cun between those two points. Isn't that so, Dr. Conner? |
| doctor: | Yes, but you still hasn't told us what a cun is. |
| student: | A cun is a unit of measurement used in TCM. Comparing it to the American inch, one cun equals about one and a third inches. What is typically used in clinic in measuring cun is the use of patient's finger width and /or breadth to represent a cun. |
| doctor: | OK, let's see if anyone else can contribute to this discussion. Kim? |
| student: | Sorry, I was daydreaming and didn't hear the question. |
| doctor: | Why do you think I called on you? (laughter in the background). Do you know how to use finger width and /or breadth as the measuring device called a cun? |
| student: | My apologies, and yes, I do actually know. The distance between the creases of the two inter-phalangeal joints of the middle finger is one cun. Clinically, I find it easier to use the width of the thumb, at the inter-phalangeal joint to measure one cun. |
| doctor: | How do we find ST36? |
| student: | As I was saying, the distance from the bottom of the patella, or the popileteal crease (which also represents the level of ST35) to the lateral malleolus is 16 cun. |
| doctor: | How do you know? |
| student: | I can answer that. There are standard basic measurements used in the proportional method. They are in our textbooks. Another, besides Rick's example, is the distance from the cubital crease, on the medial aspect of the elbow, to the inferior wrist crease being 12 cun. |
| doctor: | Excellent! You said now, by using our fingers to measure, please clarify that. |
| kim: | I just wanted to give two more examples of standard proportional measurements. One is the distance between the nipples being 8 cun and the other is the distance from yintang to the anterior hairline is 3 cun. |
| doctor: | OK, please continue, and be clear! |
| student: | OK. To clarify the use of fingers to measure, I would put the tip of the little finger of my left hand at ST35, and the tip of the little finger of my right hand on the lateral malleolus. I would then extend my index fingers toward each other, keeping my little fingers in place. Then I could visually see where the midpoint is, by observing where my index fingers are. |
| doctor: | That is the basic idea, and we will practice in location class tomorrow, so everyone can see it and understand. The distance correspondences are listed in many books. Do you have anything to add? |
| student: | One of the senior students taught me to find ST36 by placing my index finger on the lateral side of the tibia, at about the midpoint. She then said to slide my finger slowly up toward the knee, keeping light pressure on the edge of the tibia. Then when there is a slight lateral curve in the bone, the point is one finger breadth from the place where the curve begins. |
| doctor: | How would you use the proportional measurement method of location to double check? |
| student: | Well, since the distance across the 4 fingers at the center knuckle joint is 3 cun, by putting the edge of the middle joint of the small finger just on the lower border of the patella, ST36 will be just off the edge of the index finger, at the middle joint. |
| doctor: | Very, very well done. Does anyone have any comments? |
| student: | Actually, I have a very good atlas of acupuncture points that a friend in Germany sent me. I remember in that book they describe ST36 as being 3 cun inferior to ST35, one middle finger breadth lateral to the anterior crest of the tibia, at the level of the distal edge of the tuberosity of the tibia. |
| doctor: | And that slight lateral curve in the tibia, described by yourself, is actually the tuberosity described in Rick's atlas. Who can explain what a tuberosity is? |
| student: | Yes. A tuberosity is a round, elevated portion of a bone, usually at the end of a bone where a muscle is attached. |
| doctor: | Well, it is time to end our discussion. I know you all work hard and I appreciate your efforts. I am sure you will all become fine doctors and help many many people. |
| student: | That is because we have the best teacher in the world! |