Taiyang governs the superficies and controls both nutrient and defensive qi. When wind and cold attacks the human body, it first invades taiyang. Then defensive qi will take action to resist. The struggle between pathogenic factors and healthy qi in the superficies brings about taiyang meridian disease which reflects the primary stage of exogenous febrile disease. If the pathogenic factors are not relieved and enter the fu organs along the meridians, it will cause taiyang fu syndrome.

Taiyang meridian syndrome:
Taiyang meridian syndrome, the disease caused by invasion of pathogenic factors into the superficies, may be divided into taiyang wind-attack syndrome and taiyang cold-attack syndrome according to the constitution of the patients and the nature of pathogenic factors.
 
Taiyang wind-attack syndrome:
A syndrome caused by invasion of pathogenic wind into the superficies and disorder of nutrient and defensive qi.
 
Clinical manifestations:
Fever, aversion to wind, sweating, stiffness and pain in the neck and head, whitish thin tongue fur and floating and slow pulse.
 
Analysis of the symptoms:
Fever is caused by invasion of pathogenic wind into the superficies and struggle between defensive qi and pathogenic factors; sweating and aversion to wind are caused by looseness of the muscular interstices and failure of nutrient qi to keep inside because wind tends to open and disperse; stiffness and pain in the neck and head are caused by pathogenic wind attack and disorder of meridian qi because taiyang meridians converge over the head and distribute down to the neck from the head; whitish thin tongue fur is due to the fact that pathogenic factors are still retained in the skin and have penetrated inside; floating and slow pulse is the sign of external asthenia.
 
Taiyang cold-attack syndrome:
The disease caused by invasion of pathogenic cold into the superficies, obstruction of defensive qi and stagnation of nutrient qi.
 
Clinical manifestations:
Aversion to cold, fever, no sweating, or dyspnea, stiffness and pain in the neck and head, body pain, whitish thin tongue fur and floating and tense pulse.
 
Analysis of the symptoms:
Aversion to cold is caused by cold attacking the superficies, and stagnation of defensive qi; fever is caused by struggle between defensive qi and healthy qi; no sweating and dyspnea are caused by obstruction of the muscular interstices and failure of the lung to disperse and descend; pain in the head and body is caused by stagnation of nutrient qi and inhibited flow of meridian qi; whitish thin tongue fur, floating and tense pulse are the signs of wind and cold attacking the superficies.