Internal prolapse is just the mucosa hidden in the rectum and not exposed outside the anus. A true rectal prolapse is what we can see with the naked eye either as a rectal mucosa or as a circular ectasia containing the rectal muscle layer. So, why is good normal tissue not in place? For many years, medical experts have been exploring the causes of the pathogenesis. In summary, it is mainly thought to be related to human anatomical factors, increased abdominal pressure, pelvic floor tissue defects (including congenital dysplasia), wasting and other factors. 1, anatomical factors: during infancy, because the lumbosacral curvature of the spine and pelvic tilt has not yet formed, the sacrum and the spine are in the same vertical line (adult spine lumbar bend forward, sacral bend backward), rectum and sacral bend almost perpendicular, therefore, when the pressure increases after diarrhea and constipation in children, it is very easy to lead to rectal prolapse, after maturity, with the gradual formation of the sacral bend, rectal prolapse is likely to heal itself Therefore, the rectal prolapse in children is basically a mucosal prolapse, and there is no problem of the whole rectum prolapsing. Because the rectal prolapse of children is easy to self-heal, therefore, the majority of domestic anorectal professionals do not advocate surgery for children under 3 years of age. 2, multiple pregnancies and childbirth: during pregnancy, due to the influence of progesterone, the pelvic floor soft tissue tension decreases, the pelvic floor muscles tend to relax and cannot fix the rectum in a normal position, and as the fetus gradually increases, the abdominal pressure rises, and the rectum is more likely to be moved down by the pressure. In addition, childbirth can also lead to damage to the pelvic floor muscles or nerve damage, which is also one of the factors of rectal prolapse. In particular, the risk of rectal prolapse is higher in multiple mothers, and individuals have the possibility of uterine prolapse in addition to rectal prolapse. 3, various factors lead to increased abdominal pressure: some chronic cough, asthma, long-term constipation, long-term diarrhea, long-term weight-bearing distance (such as porters), etc., can often cause increased abdominal pressure, even four times higher than the normal abdominal pressure, due to the impact of high abdominal pressure leads to pelvic floor muscle overload, causing the pelvic floor muscle and rectal connection relaxation, fissure enlargement, resulting in rectal prolapse outside the anus. 4, physical weakness or malnutrition: old age and weakness or long illness, malnutrition, anorectal fat around a large number of consumed, rectal support decreased; then malnutrition also led to the pelvic floor muscle and perianal sphincter function weakened, tension decreased, the entire pelvic floor lost to rectal support fixed role, can also cause rectal prolapse, this situation is not uncommon clinical. Of course, long-term internal hemorrhoids or rectal end polyps prolapse, due to its repeated pulling, over the years, can also lead to partial or complete rectal prolapse, so for some anal prolapse disease, regardless of whether it has caused rectal prolapse, should be treated early to achieve the purpose of prevention and elimination.