Pathologically, strangulated intestinal obstruction is related to a segment of small intestine and mesentery being clamped, compressed, twisted and pulled by the same lesion, resulting in two obstruction points in this segment of small intestine, which is called closed small intestinal obstruction. This closure causes blood supply obstruction, which leads to ischemia and hypoxia of the intestinal wall, and further leads to blood stasis, edema, exudation and necrosis of this segment of small intestine. Edema and bleeding of the intestinal wall cause blood to penetrate into the intestinal cavity, and then the intestinal emptying disorder makes the intestinal contents (including liquid and gas) accumulate, which makes the proximal small intestine expand. Often, part of intestinal curvature is relatively particularly enlarged to form a special manifestation, and it is often strangulated proximal intestinal segment, which limits relaxation due to edema and thickening of intestinal wall. However, when the intestinal cavity of the strangulated segment expands obviously, although there is edema and bleeding, the intestinal wall does not thicken, but becomes thinner due to expansion. Obstruction of blood supply to the intestinal wall of the strangulated segment also reduces or disappears the intestinal peristalsis function due to intestinal muscle involvement, and extravasation of blood stasis in the intestinal wall and mesentery will lead to peritoneal effusion.