Reduced abdominal wall strength and increased intra-abdominal pressure are the two main causes of extra-abdominal hernia. 1, the abdominal wall strength reduction caused by the abdominal wall strength reduction of potential factors, the most common factors are: ① some of the tissue through the abdominal wall parts, such as the spermatic cord or uterine round ligament through the inguinal canal, the femoral artery through the femoral canal, umbilical blood vessels through the umbilical cord ring and so on; this is the human body’s anatomical defects can not be changed. ② abdominal white line due to underdevelopment can also become a weak point of the abdominal wall; ③ poorly healed surgical incisions, trauma, infection, abdominal wall nerve injury, old age, chronic disease, obesity caused by muscle atrophy is often the cause of the abdominal wall strength reduction. Biological research found that inguinal hernia patients in vivo collagen metabolic disorders in the tendon membrane, one of the main amino acid components of the hydroxyproline content is reduced, the fibroblasts in the anterior sheath of rectus abdominis muscle proliferation is abnormal, the ultrastructure contains irregular microfibers, thus affecting the strength of the abdominal wall. In addition, it was found that the plasma of smoking patients with diastasis recti had significantly higher elastic tissue dissociation activity than normal people. 2, increased intra-abdominal pressure Chronic cough, chronic constipation, urinary difficulties (such as phimosis; benign prostatic hyperplasia, bladder stones), heavy lifting, weight lifting, ascites, pregnancy, infants often cry, etc. is a common cause of increased intra-abdominal pressure. In normal people, although there are cases of increased intra-abdominal pressure from time to time, if the strength of the abdominal wall is normal, hernia will not occur. Understanding the above reasons you will know, hernia is not terrible, the clothes are torn we repair it, the operation is not too dangerous.