Study observation:Find:Pt:Posterior fossa^Fetus:Nom:US.measured
study observation:find:pt:posterior fossa^fetus:nom:us.measured
Study observation:Finding:To identify measures at a point in time:Posterior fossa^Fetus:Nominal:Ultrasound.measured
study observation:finding:to identify measures at a point in time:posterior fossa^fetus:nominal:ultrasound.measured