灵枢经·肠胃 The Intestines and Stomach
黄帝问于伯高曰：余愿闻六府传谷者，肠胃之大小长短，受谷之多少奈何？伯高曰：请尽言之，谷所从出入浅深远近长短之度：唇至齿长九分，口广二寸半；齿以后至会厌，深三寸半，大容五合；舌重十两，长七寸，广二寸半；咽门重十两，广一寸半。至胃长一尺六寸，胃纡曲屈，伸之，长二尺六寸，大一尺五寸，径五寸，大容三斗五升。小肠后附脊，左环回日迭积，其注于回肠者，外附于脐上。回运环十六曲，大二寸半，径八分分之少半，长三丈三尺。回肠当脐左环，回周叶积而下，回运还反十六曲，大四寸，径一寸寸之少半，长二丈一尺。广肠传脊，以受回肠，左环叶脊上下，辟大八寸，径二寸寸之大半，长二尺八寸。肠胃所入至所出，长六丈四寸四分，回曲环反，三十二曲也。
Huangdi asked Bogao: 'I wish to hear, among the six bowels that transmit grain, of the size and length of the intestines and stomach, and how much grain they are able to receive.' Bogao said: 'Allow me to describe this fully — the measurements of depth, distance, and length by which grain passes in and out. From the lips to the teeth is nine fen in length, and the mouth is two cun and a half in breadth. From behind the teeth to the epiglottis is three cun and a half in depth, with a capacity of five ge. The tongue weighs ten liang, is seven cun in length and two cun and a half in breadth. The throat-gate weighs ten liang and is one cun and a half in breadth. From there to the stomach is one chi and six cun in length; the stomach itself is coiled and bent, and when straightened out measures two chi and six cun in length, one chi and five cun in breadth, with a diameter of five cun, and a capacity of three dou and five sheng. The small intestine lies behind, attached to the spine, coiling to the left and folding back upon itself in layered turns; where it empties into the large intestine, it is attached externally above the navel. It winds through sixteen coils in all, two cun and a half in breadth, with a diameter of a little less than eight fen, and a length of three zhang and three chi. The large intestine coils to the left of the navel, winding round and folding downward in layered turns, circling back through sixteen coils, four cun in breadth, with a diameter of a little less than one cun, and a length of two zhang and one chi. The rectum runs along the spine, receiving what comes from the large intestine, coiling to the left and folding above and below the spine, eight cun across, with a diameter of a little more than two cun, and a length of two chi and eight cun. From the point where the intestines and stomach receive food to the point where it is expelled, the total length is six zhang, four chi and four fen, winding through thirty-two coils in all.'