File:Keibel Mall 2 552.jpg

Fig. 552. Model of the posterior abdominal wall of a human embryo of 19.4 mm greatest length

(Embryo Ma. 2, from the collection of Professor Hochstetter, Berlin. The model was prepared by my students Massard and Chome.)

The visceral layer of peritoneum is shown cut and one sees the superior recess of the omental sack. The urogenital fold is divided as far as its upper and lower ends into the mesonephric and genital folds. The mesonephric fold is bayonet-shaped and an upper sagittal, a horizontal and a lower sagittal portion, and a first and second bend may be distinguished. At the first bend the mesonephric fold is connected with the anterior abdominal wall by the inguinal fold. Between the aa. umbilicales, which still run horizontally, is the bladder plate.