This mainly includes the examination of the changes of movement of the tongue. Normally the tongue is soft and flexible, indicating sufficiency of qi and blood, normal circulation of vessels and meridians as well as normal functions of the viscera. There are four kinds of different movement of the tongue.

Stiff tongue:
The tongue is not soft; it is inflexible or stiff and immobile. Such a change of the tongue is usually seen in exogenous diseases due to exuberant heat consuming body fluid, or due to invasion of heat into the pericardium, or due to phlegm and turbid substance confusing the heart. It is also seen in miscellaneous diseases due to internal impairment caused by wind phlegm obstructing the collaterals.

Stiff tongue seen in exogenous diseases is caused either by hyperactivity of pathogenic heat which consumes body fluid and leads to malnutrition of the tongue and inflexibility of the tongue; or by invasion of heat into the  pericardium involving the spirit; or by phlegm and turbid substance confusing the heart and affecting the tongue.

Stiff tongue seen in miscellaneous diseases due to internal impairment is caused by obstruction of the tongue collaterals due to liver wind complicated by phlegm. Deep-red stiff tongue with scanty fluid is due to exuberant heat consuming body fluid or invasion of heat into the pericardium, frequently seen at the severe heat stage of exogenous diseases. Stiff tongue with greasy and thick fur seen in miscellaneous diseases due to internal impairment is caused by wind-phlegm obstructing collaterals. If the tongue suddenly becomes stiff, accompanied by aphasia, numbness of the limbs and dizziness, it is the premonitory sign of wind stroke.

Shivering tongue:
The tongue is involuntarily tremoring, indicating endogenous liver wind. Shivering tongue is caused either by consumption of blood or body fluid which fails to nourish the tendons and vessels; or by extreme heat generating wind due to exuberant heat scorching the liver meridian, or by liver yang transforming into wind. Light-whitish and shivering tongue is due to asthenia of qi and blood and endogenous asthenia-wind, usually seen in internal impairment, chronic diseases and severe diseases; reddish shivering tongue with scanty dry fur is due to consumption of yin fluid, malnutrition of the tendons and vessels and endogenous wind, usually seen at the advanced stage of exogenous febrile diseases; deep-red and shivering tongue is due to extreme heat generating wind, frequently seen at the severe heat stage of exogenous diseases; reddish and shivering tongue is due to liver yang transforming into wind, often seen in miscellaneous diseases due to internal impairment accompanied by headache and dizziness.

Deviated tongue:
The tongue is deviated to one side, suggesting wind stroke or premonitory sign of wind stroke due to liver wind complicated by phlegm or liver wind complicated by stagnation in the collaterals of the tongue.

Flaccid tongue:
The tongue is too weak to protrude and withdraw, suggesting extreme consumption of fluid or decline of qi and blood. Flaccid tongue is caused by extreme consumption of yin fluid, or by decline of qi and blood as well as malnutrition of musculature and vessels of the tongue. Deep-red and flaccid tongue with scanty fur in chronic disease due to internal impairment is due to extreme predominance of fire resulting from yin asthenia; light-whitish and flaccid tongue is due to decline of qi and blood. Reddish dry and flaccid tongue at the advanced stage in exogenous febrile diseases is due to consumption of yin by heat.

Shrunk tongue:
The tongue is contracted and cannot protrude, or cannot even reach the teeth, usually indicating critical condition. Such a syndrome is either of cold or of heat nature.

Shrunk tongue is caused either by invasion of pathogenic cold; or by stagnation of endogenous cold in the musculature and vessels of the tongue; or by extreme heat consuming fluid and causing spasm of the musculature and vessels; or by stagnation of liver wind with phlegm in the vessels of the tongue. Light-whitish or cyanotic, purplish, moist and shrunk tongue is due to stagnation of cold in the musculature and vessels of the tongue; deep-red, dry and shrunk tongue is due to extreme heat consuming fluid; bulgy and shrunk tongue with greasy fur is due to liver wind complicated by phlegm.

Protruding and wagging tongue:
The tongue that protrudes out but is unable to retreat is called protruding tongue; the tongue that frequently protrudes out but immediately draws back or licks the lips or corners of the mouth is called wagging tongue. Both conditions suggest heat in the heart and spleen. In severe cases, protruding tongue indicates invasion of pestilence into the heart or healthy qi on the verge to exhaust. Wagging tongue is the premonitory sign of endogenous wind, also seen in children with maldevelopment of intelligence.