The effects of fetal head trajectory on stress distribution in Levator Ani during vaginal delivery

The twenty LA samples of the eight female pigs were removed during practice surgical operations designed for the medical students. The pigs were 12-14 weeks old, their weight was 33-45 kg. All subjects were healthy and nulliparous. The tissue samples were extracted during general anesthesia. The muscles were cleared of fascia and cut into cuboid-shaped pieces (about 6 mm width, 4 mm thick and 10 mm length), always in the direction of muscle fibers.