J.Jpn. Surg. Soc.. 56(9): 1195-1204, 1955

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ON THE SEGMENTAL STRUCTURES OF THE LARGE INTESTINE

The large intestine is not a simple tubular organ. According to the blood supply to the large intestine from the main colonic arteries, it should be devided into four portions, first portion is the cecum, second the ascending colon, third proximal half of the transverse colon and fourth following distal portion. The borders of these segments are correspond to the beginning part of the ascending colon near the ileocecal vulve, the nearly terminal portion of the ascending colon, the nearly middle of the transverse colon and probably the end portion of the sigmoid colon. The mass movements start from these borders.
These segmentation of the large intestine is reasonable from the results of microscopic, kymographic and electroenterographic studies on its muscular layers. I found that there are some gradual differences in thickness, rhythmus, changes of action potential etc. between each of these segments, that was called "gradient" by Alvarez. The border of the anastomosis between the superior and inferior mesenteric arteries corresponds to the margin of the innervation between the superior and inferior mesenteric nerves, vagal and pelvic nerves ; and the "gradient" is marked at this portion. All these findings are same in cat and human beings.
When we study on the large intestine, I think it is important to consider that the large intestine has functional segmental structures.
(author's abstract)

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