Underlying Clinical Features

To improve understanding of the ultrasound signs it is very important to consider the underlying clinical feature that the signs represent. This will help improve interpretation and reduce the false positives e.g. due to confusion between placental lacunae and simple lakes.

Loss of retro-placental clear zone

See Clear Zone page for description and images

Lacunae and feeder vessels

See Placental lacuna page for description and images

Placental bulge

See Placental Bulge page for description and images

Both interruption of the bladder wall and bridging vessels arise from the same phenomenon - the matt of tangled blood vessels in the uterine serosa and the uterovesical fold of peritoneum between the anterior uterine wall and posterior bladder. It is important to note this is vascularity in the serosa covering the uterus not in the placenta or residual myometrium.

See here for examples.