anal vein

例句：

1. 1. The doctor performed a biopsy on the patient's anal vein to investigate for any signs of infection.
   医生对患者的肛门静脉进行了活检，以调查是否有感染的迹象。
2. 2. During surgery, the surgeon carefully dissected the anal vein to avoid damaging the surrounding tissue.
   在手术中，外科医生小心地解剖了肛门静脉，以避免损伤周围的组织。
3. 3.The patient was advised to avoid strenuous activities and to keep the anal vein clean to prevent further complications.
   患者被建议避免剧烈运动，并保持肛门静脉清洁，以防止进一步并发症。