本研究は、超音波検査により妊娠中の母体のどこに胎芽や胎子が位置するかを調べるだけでなく、分娩時に母体に向かって出現する胎子の尾鰭の向きから産道内の胎子の位置を推定することも目的とした。

The present study aimed not only to investigate where embryo and fetus located in dam's body during pregnancy by ultrasonography but also to estimate how fetal position would be within the birth canal from the orientation of fetal tail fluke which would be emerged towards dam's body at a parturition.