I have not been able to find a succinct definition of the standard of measure "cun". It appears that it could be equivalent to 0.5 cun = 1 finger width, but I'm not certain. Please explain.
The cun is a measurement relative to the patients body. Generally speaking one cun is equal to the space between the distal interphalangeal joint and the proximal interphalangeal joint on the middle finger. However, this cun can only be used on certain parts of the body when finding acupuncture points - on other points you use other relative landmarks. For example, the space from nipple to nipple is 8 cun and this 8 cun can be used to find points on the chest. These cun landmark relationships are found within the "General" link for each meridian under the "Measurements Needed" section. For example - Stomach Meridian - General Information
Hope that helps.
With the cun measurements being different, is there some measurement tool used to be a gauge? What does the normal practitioner do to gauge the correct 2mm space to puncture when the measurements can be so drastically different from person to person. I can imagine the measurement from nipple to nipple is going to be different on men than women...
After you gauge the cun in that area, how far is that cun effective for before you need to re-gauge? I can see it helps to be able to use other guides besides that cun measurement...
Is it effective to count the dips in the skin or even feel for the point in relation to other points and muscles around it instead of measuring with cun? Or even gauging patient reactions to touching the point itself?
As I stated, the cun is a relative measurement tool - relative both to the individual you are finding points on and relative to what part of the body you are finding those points. Generally, the abdomen measurements are useful on the abdomen, the chest on the chest, the leg on the leg, etc. In other words, finding the 8 cun measurement from nipple to nipple can be used to find a point that is 4 cun from the sternum on the chest but not a point on the leg that is 4 cun from the ankle. For the leg point you would use the center of the patella to the lateral malleolus which is 16 cun and divide that as appropriate to find your 4 cun distance. In clinical reality, most practitioners just "know" where the points are - this is both from training and experience as well as an intuitive touch that is developed over time. For beginners, however, and for those points that are used less often, knowing how to properly utilize the cun measurements is important.
BUT i READ THIS FROM SOMEWHERE THAT IS ACTUALLY THE WIDTH OF THE THUMB.i AM ALSO DUBIOUS ABOUT THIS MEASUREMENT AS EACH PERSON'S THUMB IS DIFFERENT FROM DIFFERENT INDIVIDUALS.cAN SOMEONE COME OUT TO CLARIFY THIS POINT.
There are a variety of basic ways to find a cun depending on where you are planning to find points (thumb, finger, your four fingers together from knuckle to knuckle, distances between body landmarks, distances between "obvious" points - such as those on the wrist crease or in a space created by a tendon, etc.). Again, as stated above, "the cun is a relative measurement tool - relative both to the individual you are finding points on and relative to what part of the body you are finding those points." You would never use your own or someone elses "cun" to find points on another person. Your statement about the cun being a "dubious" measurement because of the differences in peoples thumbs clearly misses this point.
In clinical reality, as I've also stated, practitioners are trained to "know" where the points are and very few practitioners actually measure out the point locations after they have some clinical experience. The cun is in some ways merely a training device. It is, however, much more accurate than a concrete statement which seems easier to grasp with the western mind. You could, for example, say a point is between tendon x and tendon y 5cm from the wrist crease. However, on a person with a short forearm this would be inaccurate as well as on a person with a particularly long forearm. Hence the cun - a relative measurement tool - is the only "accurate" way to consistiently measure for acupuncture points.
To help, the cun measurements that are most useful for each meridian are listed in that meridians "General" information section. The Lung Meridian, for example, relies on the following measurements:
Sternum --> Coracoid Process = 6 cun
Sternum --> Acromion Process = 8 cun
Axillary Fold --> Cubital Crease = 9 cun
Cubital Crease --> Wrist Crease = 12 cun
Note there is no mention of using the thumb or the finger to measure for points.
The Spleen Meridian uses the following measurements:
Lower border of medial condyle of tibia (SP 9) --> tip of medial malleolus = 13 cun
Upper border of symphysis pubis --> medial epicondyle of femur = 18 cun
Sternal costal angle --> CV 8 = 8 cun
Anterior midline --> Spleen line on abdomen = 4 cun
Anterior midline --> Spleen line on chest = 6 cun
Clavicular lateral measurement = 8 cun
Axillary fold --> 11th rib = 12 cun
Upper border of symphysis pubis --> umbilicus CV 8 = 5 cun
I hope this helps to make the dynamic nature of the "cun" more clear.
I think there is a tool, that is an expanding concertina-like plastic strip with holes in it, allowing you to divide between two points in equal measurements.
Have you heard of one of these?
Yes, there are a few devices for sale that are used as learning aids and in schools students often take a long piece of elastic band and mark measurements on it. The band can then be stretched to accommodate individual cun variations on different people and on different parts of the body.