Fig. 2From: Association of the second birth mode of delivery and interval with maternal pelvic floor changes: a prospective cohort studyFour-dimensional hiatus sonography (1 A: basin septal hole area; 1 C: basin septal hole circumference; 2: basin septal hole diameter; 3: anterior and posterior diameters of basin septa). (A) Resting state. (B) Retracted anus state. (C) Maximum Valsalva stateBack to article page