rule of outlet

rule of out·let

an obstetric rule for determining whether the pelvic outlet will permit the passage of a fetus; the sum of the posterior sagittal diameter and the transverse diameter of the outlet must equal at least 15 cm if a normal sized baby is to pass.

rule of outlet

an obstetric standard for determining whether the pelvic outlet will allow the passage of a fetus. It is calculated from the sum of the transverse and posterior sagittal diameters of the outlet, which must equal at least 15 cm.

rule of out·let

(rūl owt'lĕt)
An obstetric determination of whether the pelvic outlet will permit the passage of a fetus; the sum of the posterior sagittal diameter and the transverse diameter of the outlet must equal at least 15 cm if a normal-sized baby is to pass.