The Sanjiao

The sanjiao is located " separately from the zang - fu organs and inside the body. " It is divided into three parts : the upper, middle and lower jiao. Its meridian connects with the pericardium with which it is externally - internally related. Its main functions are to govern various forms of qi, and serve as the passage for the flow of yuanqi and body fluid. Yuanqi originates in the kidney, but requires the sanjiao as its pathway for distribution in order to stimulate and promote the functional activities of the zang - fu organs and tissues of the whole body. The chapter " Sixty - sixth Question " of Classics on Medical Problems, therefore, says : " The sanjiao is the ambassador of yuanqi. It circulates the three qi and distributes them to the five zang and six fu organs. "

The digestion, absorption, distribution and excretion of food and water are performed by the joint efforts of various zang - fu organs, including the sanjiao. The chapter " The Thirty - first Question " in the book of Classics on Medical Problems says : " The sanjiao is the passage of water and food. "

It is also mentioned in the eighth chapter of Plain Questions : " The sanjiao is the irrigation official who builds waterways. "

The upper, middle and lower jiao combine with their related zang - fu organs and each function differently in order to carry out the digestion, absorption, distribution and excretion of water and food. The upper jiao dominates dispersion and distribution. In other words, in combination with the distributing function of the heart and lung, the upper jiao distributes the essential qi of water and food to the whole body in order to warm and nourish the skin and muscles, tendons and bones, and regulate the skin and pores. This function is described in the eighteenth chapter of Miraculous Pivot : " The upper jiao is like a fog. "

Here " fog " is used to describe the all - pervading vapor - like stale of the clear and light essential qi of water and food.

The middle jiao dominates digestion of water and food. refers to the functions of the spleen and stomach in digesting food, absorbing essential substance, evaporating body fluid, and transforming nutrient substance into nutrient blood. This function is described in the same chapter : " The middle jiao looks like a froth of bubbles. "

" A froth of bubbles " here refers to the appearance of the decomposed state of digested food.

The lower jiao dominates the separation of the clear from the turbid and the discharge of fluid and wastes from the body. This process mainly involves the urinary function of the kidney and bladder, and the defecation function of the large intestine. The same chapter states : " The lower jiao looks like a drainage ditch. "

In other words, the turbid water continuously flows downward to be discharged. If the water passage in the lower jiao is obstructed, there may be urinary retention, dysuria and edema.

Clinically, the terms upper, middle and lower jiao are often applied to generalize the functions of the internal organs of the chest and abdominal cavity. Above the diaphragm is the upper jiao, which includes the heart and lung ; between the diaphragm and umbilicus is the middle jiao which includes the spleen and stomach ; and below the umbilicus is the lower jiao, which includes the kidney, intestines and bladder.