Rectum, anal canal injury has the following characteristics: ① rectal contents of feces, the most bacterial content, once the injury, very easy to infection; ② rectum around the lower part of the tissue gap, filled with more loose fat connective tissue, poor blood circulation, infection is easy to spread to the surrounding tissues; ③ is often accompanied by other organ injuries, such as pelvic fractures, urethral injuries and hemorrhage, etc.; ④ late complications, such as deformity, a variety of fistulas, anal complications, such as deformity, various fistulas, anal stenosis and fecal incontinence. Complications of the treatment is very difficult, the patient is hospitalized for a long time, and the prognosis is not good; ⑤ Because of the low incidence rate, physicians are not experienced in diagnosing and treating this kind of injuries, and it is easy to miss or misdiagnose, and the treatment is not timely, which is easy to lead to adverse consequences. I. Etiology 1. Penetrating injuries (1) firearms injuries: mostly seen in battle wounds, including bullets and shrapnel wounds, ballistic wounds of the skin, the skin has a ballistic inlet or outlet, no matter where the inlet is, as long as the injury channel passes through the intrinsic pelvic cavity, there is a possibility of injury to the rectum. (2) Stab wounds: stab wounds are most often caused by sharp instruments, but blunt instruments can also cause stab wounds as long as the violence is strong enough. 2. Blunt violence injuries are mostly seen in accidents with stronger violence, mostly accompanied by other organ injuries. (1) Fracture fragments puncture injuries: blunt violence causes pelvic fractures, especially fracture fragments of the sacrum and acetabulum, which can puncture the rectum. (2) Blunt violence momentarily squeezing the abdomen: can cause the sigmoid colon’s gas rushing into the rectum, due to the anus is often in a state of atresia, so that the rectum becomes closed collaterals, can cause no peritoneal coverage of the rectum rupture, this kind of injury rupture mouth is large, heavy contamination. (3) Laceration: one side of the lower limb in external traction, extreme backward extension, abduction, can cause perineal laceration, the fissure can be along the anal canal down, involving the anal canal, rectum. 3. Medical injury Less common. Pathology Generally speaking, weapon injuries and anal insertion injuries caused by a wide range and serious nature, not only cause complete rupture of the intestinal wall, extensive sphincter injuries, often accompanied by bladder, urethra, vaginal and pelvic injuries. If accompanied by large blood vessels and presacral vein injury, can cause hemorrhage and shock. The nature of medical injury is slight and small in scope, most of them only have mucosal injury, even if the intestinal wall is completely penetrated, it is limited to one place. Because of the bowel preparation before the examination, the infection is slight. Rectal injuries above the peritoneal reflex often cause purulent peritonitis, and rectal injuries below the peritoneal reflex can cause peripheral interstitial infections, such as pelvic cellulitis, posterior rectal interstitial and sciorectal fossa infections. External rectal fistula, rectovesical fistula or rectovaginal fistula are often complications of rectal injury. Anal canal injury can cause anal canal stenosis and anal incontinence. Clinical manifestations 1.shock hemorrhagic shock caused by rectal injury is relatively common, there are combined injuries, especially pelvic fracture, shock incidence is high and serious. 2. Peritonitis is mainly seen in rectal injuries above peritoneal reflexion. The severity of peritonitis is obviously related to the scope of injury, the amount of leakage of intestinal contents and the combination of injuries, and the performance of firearms injury is obvious, and the medical injury through the anus is mostly a single perforation, and the rectum is empty, and thus the symptoms are less severe. 3. Perirectal infection Rectal injury located in the peritoneum below the reflexion of the anus above the rectum, because the autonomic nerves innervating the rectum without pain, and inaccurate localization, so there is only a feeling of swelling, inflammatory stimulation can be a sharp pain, and finally, a longer period of time, the local serious infections, the formation of abscesses and the appearance of accompanied by local redness, swelling of the throbbing pain. 4. Anal area pain If the injury involves the anal canal below the anal retinaculum muscle, there will be severe pain in the anal area. 5. Anal bleeding Rectal and anal canal injuries are often accompanied by anal bleeding, sometimes in large quantities. 6. Wound fecal flow, visceral prolapse Open injury, wound with fecal discharge. Certain serious rectal injuries, in the perineum or the anal canal, there is a large omentum or small intestine prolapse 7. Other rectal and anal canal injuries are combined with a lot of injuries, due to the different combination of injuries, the clinical manifestations can be very different, and even to the combination of injuries and rectal injuries are the main manifestations are omitted from the diagnosis. Such as combined bladder, urethra injury, blood and feces in the urine. The late complications of rectal injuries include rectovesical fistula, rectovaginal fistula, rectovaginal fistula, rectal stenosis and so on. Fourth, the diagnosis of peritoneal reflex below the rectum, anal canal open injury, diagnosis is not difficult. In closed injury, if the history of trauma and clinical manifestations can be carefully analyzed, most patients can be diagnosed. However, the early clinical manifestations of rectal and anal canal injuries are often obscured by the symptoms of other organ injuries, especially those who have no wounds on the outside of the anus, so it is easy to delay the diagnosis. 1. History and clinical manifestations According to the history of lower abdominal trauma, anal insertion injury and rectum or sigmoidoscopy, the patient appeared abdominal pain, peritonitis, anal bleeding, fecal discharge from the wound or peri-rectal infection, etc. should be considered to have a rectal, anal canal trauma. 2. Wound channel According to the entrance, direction, exit, size and diameter of the wound channel, it can often be judged without rectal injury. Any wound in the lower abdomen, sacrococcygeal region, perineum or buttocks and other places of trauma, are likely to injure the rectum. Closed injuries across the pelvis, or bladder or urethra injuries should be considered as a possibility of rectal injuries, even though there is no tract. 3. Rectal palpation is the most valuable method of examination. Rectal palpation is the most valuable method of examination. It can reveal the location of the injury and the size of the wound. When the site of injury is high, blood staining of the finger cuff often suggests rectal injury. Anal examination can also determine the damage to the anal sphincter. 4. Anorectal examination can see the injury site, scope and severity. Sometimes, bowel and omentum can be found in the field of vision. Anorectoscopy should be performed when the patient’s condition permits and should not be used routinely. 5. X-ray examination (1) abdominal plain film: intraperitoneal rectal injury sometimes free gas in the abdominal cavity. (2) Pelvic plain film: the misalignment of pelvic fracture can help to determine whether there is rectal injury. About 21% of rectal injuries are accompanied by foreign body retention, which helps to diagnose rectal injuries according to the injury tract and the location of the foreign body. If a gas shadow is seen in the soft tissue of the pelvic wall, the diagnosis of extraperitoneal rectal rupture can be established. It should be noted that when rectal perforation is suspected, no matter what kind of examination is performed, the injection of air, contrast medium and barium from the anus is absolutely not allowed. 6. Peritoneal puncture: The possibility of rectal injury should be considered when fecal fluid is extracted. However, fecal fluid can also be extracted from colon injury. V. Treatment The treatment of rectal and anal canal injuries includes rectal and anal canal injuries and the treatment of various combined injuries. In principle, the earlier the surgery, the better, according to the location and scope of the injury, choose different treatment programs. 1. The treatment of rectal injury above peritoneal reflexion is the same as that of colonic injury. 2. Injuries below the peritoneal reflex are treated with one-stage suture repair of rectal fissure and/or complete diversionary sigmoidostomy, full drainage of presacral space via paracolic approach or resection of coccyx, and flushing of distal end of colon via fistula, removal of fecal matter residue in the rectum in order to facilitate healing of the fissure. Rupture of the upper rectum should be repaired by dissection, and at the same time, the sigmoid double cylinder stoma should be performed, and the stoma should be closed after 2 to 3 months. When the lower rectum is ruptured, the perirectal space should be adequately drained to prevent the spread of infection. For this patient, sigmoidostomy should also be performed to reroute feces until the wound heals. Rectal injury combined with pelvic hemorrhage should be aggressively antiresorptive, with dissection and ligation of bilateral internal iliac arteries. Medium and small vein rupture or blood seepage from fracture breaks can be stopped by tamponade and compression. Combined with bladder rupture and urethral rupture, suprapubic cystostomy should be performed at the same time.