The S-shaped ductus arteriosus.
Brown
D L
DL
Benson
C B
CB
D004373:Ductus Arteriosus / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D011247:Pregnancy; D014463:Ultrasonography