[custom_adv] The flush toilet was first invented in the late 16th century by Sir John Harington. But it was only during the 19th century that seated toilets became available for mass use. [custom_adv] Most of the Western world still sits to defecate, while squatting is favoured in the developing world. The process of passing bowel motions or defecation is a lot more complicated than you might imagine. [custom_adv] First, the rectum contracts as it fills up with stools. This causes the smooth muscle of the anal canal to relax. The puborectalis muscle, which loops around the rectum like a sling, normally pulls the rectum forward to create a tight angle - known as the anorectal angle. [custom_adv] During defecation, the puborectalis muscle will relax and the anorectal angle will widen. Squatting widens the anorectal angle even more to allow a clearer and straighter passage for stools to pass through the anal canal. [custom_adv] The volunteers sat on toilets of different heights (42cm and 32cm high) and also squatted over a plastic container. They recorded data for six consecutive bowel motions in each posture. [custom_adv] The average time for passing a bowel motion during squatting was 51 seconds, compared to the average times for the lower and higher toilet seats: 114 and 130 seconds respectively. Participants found defecation easier while squatting than when seated. [custom_adv] The researchers found the anorectal angle had greater widening in the squatting position. Participants also had less abdominal straining while squatting. People who strain excessively are more prone to developing tears of the anal lining, known as a fissure.
