Observation of the Tongue
Observation of the tongue, also known as
tongue diagnosis, is an important procedure in diagnosis by inspection. It
provides primary information for the Chinese physicians to make diagnosis.
Physiology of the tongue.
The
tongue directly or indirectly connects with many zang - fu organs through the
meridians and collaterals. The deep branch of Heart Meridian of Hand - Shaoyin
goes to the root of the tongue ; the Spleen Meridian of Foot - Taiyin traverses the
root of the tongue and spreads over its lower surface ; the Kidney Meridian of
Foot - Shaoyin terminates at the root of the tongue. So the essential qi of the
zang - fu organs can go upward to nourish the tongue, and pathological changes of
the zang - fu organs can be reflected by changes in tongue conditions. This is why
the observation of the tongue can determine the pathological changes of the
internal organs.
- Heart and lung
- Spleen and Stomach
- Kidney
- Liver and gallbladder
Observation of the tongue includes the
tongue proper and its coating. The tongue proper refers to the muscular tissue
of the tongue, which is also known as the tongue body. The tongue coating refers
to a layer of " moss " over the tongue surface, which is produced by the
stomach qi. A normal tongue is of proper size, soft in quality, free in motion,
slightly red in color and with a thin layer of white coating which is neither
dry nor over moist.
The tongue is divided into four areas,
namely, tip, central part, root and border. The tip of the tongue often reveals
the pathological changes of the heart and lung ; its border reveals those of the
liver and gallbladder ; its central part reveals those of the spleen and stomach ;
and its root reveals those of the kidney. This method of diagnosing the
pathological changes of the zang - fu organs by dividing the tongue into
corresponding areas is clinically significant.
Tongue diagnosis
Tongue proper. This is to observe
the color and form of the tongue proper.
Color of the tongue proper
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Pale tongue : A pale tongue is less red
than a normal tongue, and indicates syndromes of deficiency type and cold
syndromes caused by deficiency of yang qi or insufficiency of qi and blood.
-
Red tongue : A red tongue is bright red
and redder than a normal tongue. It indicates various heat syndromes
including interior heat syndromes of excess type and interior heat syndromes
of deficiency type due to yin deficiency.
-
Deep red tongue : A deep red tongue
indicates an extreme heat condition. In exogenous febrile diseases, it
indicates invasion of the ying and xue ( blood ) systems by pathogenic heat.
In endogenous diseases, it indicates yin deficiency leading to hyperactivity
of fire.
-
Purple tongue : A blue purple tongue
indicates stagnation of blood which is related to either cold or heat. A
deep blue purplish tongue, dry and lustreless, is related to heat, whilst a
pale purplish and moist tongue is related to cold. The presence of purplish
spots on the tongue surface also indicates stagnation of blood.
Form of the tongue proper
-
Swollen tongue : A swollen tongue is
larger than normal. If a swollen tongue is delicate in quality and pale in
color, and with tooth prints on the border, it indicates yang deficiency of
the spleen and kidney. The condition is due to impaired circulation of body
fluid producing harmful water, retained fluid, phlegm and damp. If a swollen
tongue is deep red in color occupying the entire space of the mouth, it
indicates excessive heat in the heart and spleen. If a swollen tongue is
blue purplish and dark, it indicates toxicosis.
-
Thin
tongue : A thin tongue is smaller and thinner than normal. A thin and pale
tongue indicates deficiency of qi and blood. A thin, dry and deep red tongue
indicates hyperactivity of fire due to deficiency of yin in which body fluid
is consumed.
-
Cracked tongue : Irregular streaks or
cracks on the tongue indicate excessive heat consuming body fluid if the
tongue is deep red in color, and indicate deficiency of blood if the tongue
is pale. A cracked tongue may be present in a normal person. If so, the
cracks are not deep, and remain there all the time unchanged. This is
considered normal.
-
Thorny tongue : The papillary buds over
the surface of the tongue swell up like thorns. A thorny and red tongue
indicates accumulation of pathogenic heat in the interior. The more severe
the pathogenic heat is, the more enlarged and profuse the thorns will be.
-
Deviated tongue : A deviated tongue
indicates windstroke or early threatening signs of windstroke.
-
Rigid tongue : A rigid tongue lacks
flexibility and is difficult to protrude, retract or roll. A rigid tongue
seen in exogenous febrile diseases often indicates invasion of the
pericardium by heat, retention of turbid phlegm in the interior, or
excessive pathogenic heat consuming body fluid. A rigid tongue present in
endogenous diseases indicates wind stroke or early threatening signs of
windstroke.
-
Flaccid tongue : A flaccid tongue is
weak in motion, and often indicates extreme deficiency of qi and blood or
consumption of yin fluid depriving the tongue of the nourishment. If a
flaccid tongue is pale, it indicates deficiency of qi and blood. If it is
deep red, it indicates collapse of yin.
Tongue coating :
Quality of the tongue coating
-
Thick coating and thin coating : The
tongue coating is considered thin if the tongue proper can indistinctly be
seen through it, and considered thick if the tongue proper can not be seen
through it. One can understand the severity of the pathogenic factors and
progression of the pathological conditions by distinguishing the thickness
and thinness of the tongue coating. Generally speaking, a thin tongue
coating is present if the superficial portion of the body is affected in a
disease, or if the disease is due to deficiency of the anti - pathogenic qi.
Retention of damp, phlegm or food in the interior, or inward transmission of
the pathogenic factor from the exterior may produce a thick tongue coating.
Thickening coating indicates inward transmission of the pathogenic factor
from the exterior, and is a sign of aggravation of the disease. Thinning
coating points to gradual elimination of the pathogenic factor, and is a
sign of alleviation of the pathological conditions.
-
Moist coating and dry coating : One can
understand the condition of the body fluid. by distinguishing the moisture
and dryness of the tongue coating. A normal tongue coating is moist and
lustrous, which is the manifestation of normal dissemination of the body
fluid. A dry tongue coating, which looks coarse and feels lacking moisture
indicates consumption of body fluid due to excessive heat or consumption of
yin fluid not allowing it to nourish upwards. If there is excessive moisture
over the tongue surface, and the saliva dribbles when the tongue is stuck
out in a severe case, it is a slippery tongue coating. The condition is
caused by upward flooding of harmful water and damp.
-
Sticky coating and granular coating :
Both sticky and granular tongue coating help deduce the turbid damp in the
intestines and stomach. It is a sticky coating if the tongue is covered by a
turbid layer of fine greasy substance which is hard to be scrubbed. A sticky
tongue coating is often seen in syndromes resulting from retention of turbid
damp and phlegm or retention of food. It will be a granular coating if the
granules on the tongue surface are coarse, loose and thick like residue of
making soy bean curds, and easily scrubbed. A pasty tongue coating often
results from excessive yang heat bringing the turbid qi in the stomach
upwards. It is also seen in syndromes caused by retention of turbid phlegm
or retention of food.
-
Peeled coating : The tongue with a part
of its coating peeling off is known as " geographic tongue. " It is
a sign of consumption of qi and yin of the stomach. If the entire coating
peels off leaving the surface mirror smooth, the condition is known as
glossy tongue. It is a sign of exhaustion of the stomach yin and severe
damage of the stomach qi.
Color of the tongue coating
-
White coating : A thin and white coating
is normal. Yet a white coating may appear in an illness. If so, it indicates
exterior syndromes and cold syndromes. A thin and white coating is present
in exterior cold syndromes, whilst a thick and white coating is seen in
interior cold syndromes.
-
Yellow coating : A yellow coating
indicates interior syndromes and heat syndromes. The deeper yellow the
coating is, the more severe pathogenic heat it indicates. A light yellow
coating points to mild heat ; a deep yellow coating to severe heat ; a burnt
yellow coating to accumulation of heat.
-
Grey coating : A grey coating indicates
interior syndromes, and may be seen in interior heat syndromes or syndromes
resulting from cold and damp. If a grey coating is yellowish and dry, it
signifies consumption of body fluid due to excessive heat. If a grey coating
is whitish and moist, it implies retention of cold damp in the interior or
retention of phlegm and fluid. As a grey coating often develops into a black
coating, a greyish black coating is seen.
-
Black coating : A black coating
indicates interior syndromes due to extreme heat or excessive cold. A black
coating is often the outcome of the further development of a yellow coating
or a grey coating. It is present at the severe stage of an illness. If a
black coating is yellowish and dry, possibly with thorns, it signifies
consumption of body fluid due to extreme heat. A pale black and slippery
coating implies excessive cold due to yang deficiency.
Precautions in tongue diagnosis
-
As each disease undergoes a complicated
process, the conditions of the tongue proper and its coating are the
manifestations of interior complicated pathological changes. The conditions
of the tongue proper mainly reflect deficiency or excess of the zang - fu
organs and relative strength of the essential qi. The conditions of the
tongue coating reflects the depth and nature of the invading pathogenic
factors. A comprehensive analysis of the conditions of both the tongue
proper and its coating is required on the basis of their respective
indications. The condition of the tongue proper and that of its coating are
generally conformable ; the disease to be indicated is often the outcome of
combining the two. For instance, retention of heat of excess type in the
interior produces a red tongue with a dry and yellow coating ; a pale tongue
with a moist and white coating is often present in cold syndromes of
deficiency type. But such situations as the condition of the tongue proper
does not agree with the condition of its coating may occur. Only by a
comprehensive analysis can reliable information be provided for further
differentiation of syndromes.
-
It is desirable to observe the tongue
in direct natural light. The patient is required to protrude the tongue
naturally.
-
Some food and drugs may color the
tongue coating, and the thickness and moisture of the tongue coating may
change after eating or scraping the tongue. Attention should be paid to the
exclusion of false phenomena induced by such factors in the clinical
situation.
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