Umbilical cord vein/artery running through amniotic sac causing a "bridge".
Again the large vein/artery running through the amniotic sac. Notice the "bridge". Note the umbilical cord is attached to the side of the placenta, not centered.
Umbilical cord attached on amniotic sac.
Baby side, notice the thin cord.
Mother's side. Most placenta's are round. This one is kidney shaped, missing a lobe.