ectocolon

例句：

1. 1. The doctor performed a colonoscopy to examine the rectum.
   医生进行了结肠镜检查以检查直肠。
2. 2.The patient was admitted to the hospital for treatment of an infection in the outer rectum.
   患者因外肛管感染被收治入院治疗。
3. 3. The patient had to undergo surgery to repair the damaged rectum.
   患者不得不接受手术来修复受损的直肠。