Geographic tongue

Keywords: Chinese medicine, pattern discrimination, tongue diagnosis

In last month's issue of The Townsend Letter, I described the role of pulse diagnosis in standard professional Chinese medicine. This month I would like to discuss tongue diagnosis or, more properly, tongue examination (she zhen) in Chinese medicine. While practitioners of acupuncture and Chinese medicine take into consideration the patient's disease diagnosis, they mainly base their treatment on the patient's individualized Chinese medical pattern or zheng. A pattern is a named and recognized standard group of signs and symptoms, and there are more than 300 such patterns in professional Chinese medicine. Each pattern is defined by a group of general signs and symptoms, tongue signs, and pulse signs. Therefore, one can say that tongue examination comprises one third of the Chinese medical process of pattern discrimination. In terms of the four examinations (si zhen) of Chinese medicine, tongue examination is a special subcategory of visual inspection (wang zhen).

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The history of tongue diagnosis in Chinese medicine

Descriptions of diagnostically significant pathological changes in the tongue and its fur in the Chinese medical literature date back to the Nei Jing (Inner Classic), the "Bible" of Chinese medicine which was compiled in the late Han dynasty (circa 200 A.D. or C.E.). Throughout the succeeding dynasties, famous Chinese doctors added more and more tongue observations to the Chinese medical literature. However, the first surviving Chinese medical text to deal exclusively with tongue examination dates from 1341 during the Yuan or Mongol dynasty. This book was written by Du Qing-bi and was based, in part, on an earlier book by a Master Ao which has not survived. This book contained 36 color illustrations of the tongue and its fur corresponding to various patterns of disharmony and their pulses. Since that time, numerous such books have been published with an ever-increasing number of illustrations until today, when we have books full of color photographs of tongues, sets of colored slides of tongues, and even sets of colored plastic tongue models to help students and practitioners learn this important diagnostic art. For instance, in 1906, Liang De-yan wrote She Jian Bian Zheng (Pattern Discrimination by Examining the Tongue). This book describes 148 tongue types and their pattern indications. Today, tongue examination is taught at all colleges of Chinese medicine in the People's Republic of China and is the frequent subject of articles published in Chinese medical journals.

The relationship of the tongue to the interior of the body

In Chinese medicine, it is believed that every part of the body contains a "holographic" image of the entire rest of the body. This holographic image is sometimes referred to in English as a homunculus or little man. Therefore, there is a "map" of the entire body on the ear, hand, foot, face, eye, and even the lateral edge of the first metacarpal bone. Sites on these maps reflect pathological changes in the corresponding body parts and, at least in some cases, stimulation of these sites can be used to treat those corresponding body parts. Anyone familiar with foot reflexology will understand this concept. Unlike the nose, hands, and feet, the tongue is an internal organ which can be seen from the outside of the body. Therefore, in Chinese medicine, the tongue is believed to be a hologram or homunculus of the organs located in the cavity of the torso. This means that Chinese medical practitioners believe that certain areas of the tongue correspond to specific viscera and bowels. Pathological changes in a given area of the tongue are thus believed to indicate pathological changes in the corresponding viscus or bowel. The accompanying diagrams show these correspondences.

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Tongue body and fur

Chinese medical practitioners look at two main things when they look at the tongue. These two things are 1) the tongue body, and 2) the tongue fur. Inspection of the tongue body is also divided into two: inspection of the tongue shape and inspection of the tongue color. Inspection of the tongue fur is divided into inspection of the thickness of the fur and consistency and inspection of its color and moisture. According to Chinese medical textbooks, the normal tongue color is pale red similar to a skinned chicken. The normal tongue body or shape is neither too thick nor too thin and is not cracked or crevassed. The normal tongue fur is thin in thickness and white in color, thus appearing almost transparent. Further, the sublingual veins are not dark, tortuous, and distended. Such a tongue indicates that qi and blood are sufficient and flowing freely, that yin and yang are in relative balance, and that, in particular, the stomach is functioning harmoniously.

In terms of deviations from this norm, a tongue which is thicker than normal indicates a yin repletion due to nonmovement and nontransportation of water fluids, while a tongue which is thinner than normal indicates an insufficiency of righteous yin, including qi and blood. A tongue which is paler than normal indicates a blood vacuity. A tongue which is redder than normal indicates heat. A tongue which is blue indicates cold, while a tongue which is purple and dark indicates blood stasis. Static speckles or spots, brownish papillae, also indicate blood stasis in the organ corresponding to their location on the tongue as do static macules, black and blue spots on the tongue. Another indication of blood stasis, this time primarily in the chest, are distended, dark, tortuous sublingual veins. If the tip of the tongue is red, this means heat specifically in the heart, but, if it is the sides of the tongue that are red, this indicates heat in the liver-gallbladder. Cracks and crevasses on the surface of the tongue can mean either of two things. If the tongue is not red, crevasses and cracks in the tongue mean longstanding spleen vacuity. If the tongue is red, then they mean chronic and enduring yin vacuity. And finally, if the tongue quivers excessively when presented, this indicates stirring of internal wind.

The tongue fur is believed to be a reflection of the stomach qi or stomach function. If the tongue fur is thin and white, this means that the stomach is functioning normally. It is dispersing and downbearing food properly and it is not too hot. If the fur becomes thicker than normal, this means that the stomach is not dispersing the food properly but that the food is backing up in the stomach and intestines. If the fur is thicker than normal and dry, it shows that there is also damage to the stomach and intestinal fluids. If the fur turns yellow, it indicates pathological heat. If it further turns brown or black, then this pathological heat is even worse. If the tongue fur is glossy and slimy, it indicates an accumulation of dampness and turbidity, but if it is patchy and geographic, this means that, although there is damp heat, the heat is damaging yin fluids. So this is a more complicated pattern of disharmony. While the color and shape of the tongue only change slowly over the course of hours or even days, the tongue fur can change within a single hour.

Inspecting the tongue

In China, when the practitioner wants to see the patient's tongue, they say, "Kan kan she tai," "Let me see your tongue and fur." Typically, the patient is sitting upright in a room well lit with natural light. The patient should then stick out his or her tongue moderately far. Like so much else in Chinese medicine, the patient should neither stick their tongue out too far, which distorts both its shape and color, or too little, which makes the tongue impossible to assess. The practitioner should look at the tongue in short, repeated bouts so that the tongue does not change color or shape due to the strain of holding it in an unusual place. Instead the practitioner asks the patient to stick out their tongue, writes down an impression, and then tells the patient to relax and close their mouth again. This procedure is repeated several times until the practitioner feels confident he or she has a good picture of the patient's tongue body shape and color and its fur's thickness, color, and moisture. This procedure can be done relatively quickly and easily, does not require any special equipment, and is painless and nonthreatening to most patients. If there is no natural light, then the practitioner must make allowance for the color of the light. For instance, incandescent light makes the fur look yellowish when it's not, and fluorescent light makes the tongue look bluish or purple when it's not.

Much easier than pulse examination

Chinese tongue examination is much, much easier to master than Chinese pulse examination. The basics of this art can be learned in a single day or less. Therefore, many students of Chinese medicine place more emphasis on the tongue than the pulse during the early years of their practice, effectively using the tongue to teach themselves the pulse over time. Because the tongue is inspected visually, interrater reliability is quite good. It is relatively easy to agree whether there are teeth-marks on the edges of the tongue or cracks down its middle. Likewise, it is relatively easy to agree on color, thickness and color of tongue fur, and the moistness of the tongue.

An example of the use of tongue examination in clinical practice

The patient was a 36 year-old female who was seen for the common cold. She had had a sore throat, fever, chills, nasal congestion, profuse phlegm, and cough for four days. In addition, she was fatigued and had lost her appetite. When the woman had first come down with the cold, she had gone to her local health food store where she had purchased Yin Qiao Wan (Lonicera & Forsythia Pills), a common Chinese ready-made medicine for a wind heat external contraction pattern of the common cold. However, she had taken only the dosage of these pills recommended on the package (which is typically too little) and, even then, had missed a number of doses. Because she had not gotten better as expected, she came in for a professional examination. Beside the forgoing signs and symptoms, the patient's pulse was fine, bowstring, and slightly rapid and her tongue was enlarged with teeth-marks on its edges, normal in color, but was covered with thicker than normal fur. This fur was white on one side of the body and yellow on the other. In this case, the pulse is really not very revelatory on its own. It could indicate a number of different patterns. However, the tongue was very accurate in its indications.

Based on the enlargement of the tongue with teeth-marks on its edges, I knew that there was a chronic spleen qi vacuity. This had led to a righteous qi vacuity and, thus, the body's susceptibility to external invasion and its inability to throw off the evil qi. Because the spleen qi moves and transforms water fluids in the body, the swollen tongue indicated that water fluids had accumulated, thus making a lot of dampness and phlegm. Although "the spleen is the root of phlegm engenderment, the lungs are the place where phlegm is stored." Such spleen vacuity was confirmed by the fatigue and lack of appetite. The tongue fur which was white on one side and yellow on the other showed that the evil qi was half inside and half outside. This is called a shao yang aspect disease. It means that there was still evil qi lodged in the exterior of the body but that some of this evil qi had made it to the interior. This then explained why the Yin Qiao Wan had not adequately dealt with the condition and was certainly inappropriate now. Yin Qiao Wan, as an exterior-resolving formula, only clears wind heat evils from the exterior of the body. Now this patient needed a shao yang aspect harmonizing formula (shao yang fen he fang). This is an entirely different category of Chinese herbal formula.

When administered a modification of Xiao Chai Hu Tang (Minor Bupleurum Decoction), the classic shao yang aspect harmonizing formula, the woman's appetite immediately returned, her fever went down, her chills abated, and her energy began to return. In terms of tongue examination, the yellow fur on one half of her tongue disappeared and the entire coating turned white. By the second day, her cough had stopped and she was only producing a slightly abnormal amount of mucus. By the third day, she was back to work, feeling relatively normal, and her tongue fur was thin and white. This shows both how tongue examination is used in Chinese medicine and how clinically important its findings can be. In this particular case, the half white and half yellow tongue fur is a clear and definite indication of the stage and pattern of this disease. It showed that the Chinese herbs the woman was currently taking on her own were not the right ones and pointed unequivocally to the right formula which, when prescribed, did the job expected of it.

Copyright [c] Blue Poppy Press, 2004. All rights reserved.

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Going further

For those interested in learning more about Chinese medical tongue examination, the following English language books are all good sources of information:

Atlas of Chinese Tongue Diagnosis by Barbara Kirschbaum, Eastland Press, Seattle, 2000, ISBN 0-939616-33-5

Atlas of the Tongue and Lingual Coatings in Chinese Medicine by Song Tian-bin, People's Medical Publishing House & Editions Sinomedic, Bejing & Strabourg, 1986, ISBN (none)

Practical Diagnosis in Traditional Chinese Medicine by Deng Tie-tao, trans. by Marnae Ergil & Yi Su-mei, Churchill Livingstone, Edinburgh, 1999, ISBN 0-443-04582-8

Tongue Diagnosis in Chinese Medicine by Giovanni Maciocia, Eastland Press, Seattle, 1995, ISBN 0-939616-19-X

Copyright [c] Blue Poppy Press, 2004.

All rights reserved.

by Bob Flaws, Dipl. Ac & CH, FNAAOM, FRCHM

COPYRIGHT 2004 The Townsend Letter Group
COPYRIGHT 2004 Gale Group