The small intestine and its mesentery occupy a large volume in the abdominal cavity, are widely distributed, and lack strong protection, making them vulnerable to damage. They account for about 1/4 of abdominal organ injuries and rank first among abdominal organ injuries during wartime. Blunt injuries are caused by the violent squeezing of the small intestine against the lumbar vertebral body. The squeezing of the intestinal contents rapidly moves upward and downward, up to the Treitz ligament and down to the ileocecal valve, forming a high-pressure closed loop intestinal segment. Perforations are mostly within 70 cm of the upper and lower ends of the small intestine. Occasionally due to indirect violence (falling from a height, sudden stop during rapid movement), the intestine vibrates violently in the abdominal cavity due to inertia, and the gas and liquid in the intestine are suddenly transmitted to a certain section of the intestinal loop, causing a sudden increase in intracavitary pressure and rupture of the intestine. A few are caused by excessive contraction of the abdominal muscles or iatrogenic reasons.