(1) According to the causes of obstruction, it can be divided into three categories. 1. Mechanical intestinal obstruction. It is the most common in clinical practice. More than 90% of acute intestinal obstructions are caused by mechanical factors that lead to narrowing or occlusion of the intestinal cavity, preventing the passage of intestinal contents. For example, intestinal adhesions, intestinal inflammation or tumors, external masses compressing the intestine, strangulated hernias, intussusception, intestinal volvulus, and ascaris lumbricoides blocking the intestinal cavity all fall under this category.