Mean surface shape of a human placenta
  The chorionic plate (or "fetal surface") of the human placenta is drawn as round, with the umbilical cord inserted roughly at the center, but variability of this shape is common. The average shape of the chorionic plate has never been established. The goal of this work is to measure the average shape in a birth cohort. 
Michael Yampolsky, Oleksandr Shlakhter, Carolyn M. Salafia, Danielle   Haas