母羊胚胎孕囊超声影像

Transabdominal ultrasound of twin embryonic vesicles at 35 days’ gestation in a ewe. At approximately 35 days, a transabdominal ultrasonographic examination of a ewe with a twin pregnancy typically reveals two distinct fluid‑filled embryonic vesicles within the uterine lumen. These appear as anechoic (black) round to oval structures, each surrounded by a thin, smooth, echogenic (bright) rim representing the developing trophoblastic membranes.