特殊用法free villus1.游离绒毛2.【解】自由绒毛intestinal villus1.肠绒毛placental villus1.胎盘绒毛pleural villus1.胸绒毛primary villus1.初级绒毛secondary villus1.次级绒毛2.【解】续发性绒毛synovial villus1.滑膜绒毛trophodermal villus1.滋养层绒毛