图示：小肠肠套叠。肠的一部分嵌入到另一部分中，明显影响来自肠系膜的血液供应。梗死发生后呈暗红色外观，图为外科切除部分。肠套叠临床少见。婴幼儿和儿童多发生于回盲瓣且常没有明显的诱因，成人多见于小肠且常有明显的诱因。
This is intussusception of the small intestine. One portion of bowel has telescoped inside another distal portion, compromising the blood supply from the mesentery. The result is infarction, evidenced by the dark red appearance, and this portion of bowel was surgically excised. Intussusception is a rare event. In infants and children, this event happens at the ileocecal valve and often has no obvious etiology. When intussusception occurs in adults, the small intestine is usually involved and the precipitating cause is a mass projecting into the lumen that was caught by a peristaltic wave and pulled distally.