Fig. 1From: Transperineal ultrasound of fetal head progression in prolonged labor: women’s acceptance and ability to predict the mode of deliveryTPUS showing angle of fetal head progression (α) reaching 121°. Two lines are drawn; one is placed through the midline of the symphysis pubis, and the other line is running through the caudal apex of the symphysis pubis to the fetal skull tangentiallyBack to article page