an increase in pressure within the rectum forces apart the walls of the anal canal, allowing the fecal matter to enter the canal. The rectum shortens as material is forced into the anal canal and peristaltic waves push the feces out of the rectum. The internal and external anal sphincters along with the puborectalis muscle allow the feces to be passed by muscles pulling the anus up over the exiting feces. Voluntary and involuntary control The external anal sphincter is under voluntary control whereas the internal anal sphincter is involuntary. In infants, the defaecation occurs by reflex action without the voluntary control of the external anal sphincter. Defecation is voluntary in adults. Young children learn voluntary control through the process of toilet training. Once trained, loss of control, called fecal incontinence, may be caused by physical injury, nerve injury, prior surgeries (such as an episiotomy), constipation, diarrhea, loss of storage capacity in the rectum, intense fright, inflammatory bowel disease, psychological or neurological factors, childbirth, or death. Sometimes, due to the inability to control one's bowel movement or due to excessive fear, defecation (usually accompanied by urination) occurs involuntarily, soiling a person's undergarments. This may cause significant embarrassment to the person if this occurs in the presence of other people or a public place. Posture The positions and modalities of defecation are culture-dependent. Squat toilets are used by the vast majority of the world, including most of Africa, Asia, and the Middle East. The use of sit-down toilets in the Western world is a relatively recent development, beginning in the 19th century with the advent of indoor plumbing. Disease Regular bowel movements determine the functionality and the health of the alimentary tracts in human body. Defecation is the most common regular bowel movement which eliminates waste from the human body. The frequency of defecation is hard to identify, which can vary from daily to weekly depending on individual bowel habits, the impact from the environment and genetic. If defecation is delayed for a prolonged period the fecal matter may harden, resulting in constipation. If defecation occurs too fast, before excess liquid is absorbed, diarrhea may occur. Other associated symptoms can include abdominal bloating, abdominal pain, and abdominal distention. Disorders of the bowel can seriously impact quality of life and daily activities. The causes of functional bowel disorder are multifactorial, and dietary habits such as food intolerance and low fiber diet are