secondary anal vein

例句：

1. 1.The surgeon removed the secondary anal vein to relieve the patient's pain.
   外科医生切除了次级肛门静脉，以缓解病人的疼痛。
2. 2. During surgery, the surgeon carefully dissected the secondary anal vein to avoid damaging the surrounding tissue.
   在手术过程中，外科医生小心地解剖次级肛门静脉，以避免损伤周围的组织。
3. 3. The patient was given medication to alleviate the symptoms of secondary anal vein.
   患者被给予药物来缓解次级肛门静脉的症状。