The feeling of incomplete bowel movement is the feeling of having unclean bowel movements and wanting to defecate after relieving the bowel movement. 1, intestinal inflammation and functional diseases (1) ulcerative colitis Ulcerative colitis is a chronic non-specific inflammation of the intestine of unknown origin, lesions from the rectum, can spread throughout the large intestine, mild patients can be manifested as an increase in the number of stools, a sense of incomplete defecation, mucus stool, etc.. Colonoscopy can be helpful for diagnosis. (2) Irritable bowel syndrome Irritable bowel syndrome is a functional disease of the intestine, which can be clinically divided into diarrheal irritable bowel syndrome, constipated irritable bowel syndrome, mixed irritable bowel syndrome and indeterminate irritable bowel syndrome. Some patients have an increased number of stools, 5 to 6 times a day, or even 10 times a day, and often have a feeling of incomplete defecation, patients may also have abdominal pain, bloating and other symptoms, abdominal pain is usually relieved after defecation. (3) Bacterial dysentery Chronic bacterial dysentery is a chronic inflammatory disease of the intestine caused by infection with Bacillus dysenteriae, the lesion is usually located in the rectum and sigmoid colon, the patient can show an increase in the number of stools, the feeling of incomplete defecation and the urgency, mucus-purulent stool. (1) Rectal cancer Rectal cancer is a malignant tumor originating from the rectum, the pathology is mostly adenocarcinoma, the clinical manifestations are increased number of stools, the feeling of incomplete defecation, mucus and blood stools. Most rectal cancers can be palpated by anorectal examination, which is a hard, unsmooth and inactive mass in the rectum, and the finger stained with blood. The lesion can be directly observed under proctoscopy and fiberoptic colonoscopy, and the tissue can be taken for pathological examination. (2) Anal canal cancer Anal canal cancer is a malignant tumor originating from the anal canal. Pathologically, it is roughly divided into epithelial cell tumors (such as squamous epithelial carcinoma, basal cell carcinoma, adenocarcinoma, etc.), non-epithelial cell tumors (such as sarcoma, lymphoma, etc.) and malignant melanoma, mainly squamous epithelial carcinoma. The clinical manifestation of this disease is not obvious in the early stage, and the clinical manifestation in the progressive stage is similar to rectal cancer, which also manifests as increased frequency of stool, incomplete feeling of defecation, mucopurulent stool, thin stool, etc., but patients often have anal pain, which is more obvious after stooling. (3) colorectal carcinoid tumor colorectal carcinoid tumor, also known as silverophilic cell tumor, occurs in the silverophilic cells of intestinal mucosal glands, which are chromophobic in nature, most colorectal carcinoid tumors are asymptomatic, when they are symptomatic, mild blood in stool is common, which is caused by the tumor penetrating the surface mucosa and forming ulcers or erosions, and can also manifest as increased frequency of stool, incomplete defecation, constipation, diarrhea and anorectal pain. When the tumor is enlarged, abdominal distension, abdominal pain and other symptoms of intestinal obstruction may appear. Rectal carcinoid tumor is mostly located in the anterior or lateral wall of rectum, and in the early stage, it is mostly 0.3~0.5cm round or oval nodules, located in the submucosa, with smooth and intact surface mucosa, pale color compared with normal mucosa, slightly hard texture without pressure and easy to push down. It is yellow or brownish yellow under the colonoscope. Barium enema can be seen as polyp-like masses or apple nucleus-like changes similar to the annular surface of colon cancer. 3.Anorectal and pelvic floor diseases (1) Internal hemorrhoids Internal hemorrhoids are soft venous masses formed by enlarged varicose veins in the submucosal hemorrhoid plexus located above the anal dentate line and not covered by the skin of the anal canal. Internal hemorrhoids are mostly located at the KC position 3, 7, and 11 points, and are divided into vasomatous, fibrotic, and varicose veins according to the different pathological changes of the internal hemorrhoid tissue. The main clinical manifestations are bleeding during stool, but when the hemorrhoid nucleus is large, it can prolapse out of the anus, and there can be a feeling of incomplete defecation, anal swelling, and difficulty in defecation. (2) Intra-rectal mucosal prolapse Intra-rectal mucosal prolapse refers to the folding of the entire proximal rectal wall or the mucosal layer alone into the distal intestinal cavity or anal canal during defecation, not exceeding the outer edge of the anus, and persisting after the fecal mass is expelled. The clinical manifestations of the disease include a feeling of incomplete defecation, obstruction, anal swelling, increased frequency of stool, sometimes bleeding mucus and blood stool, abdominal pain, diarrhea, abnormal urination and other symptoms. Anal finger diagnosis can reveal mucosal relaxation in the lower rectum or mucosal accumulation in the intestinal cavity. Anoscopic diagnosis can see the rectal mucosa loosening and prolapsing downward, stuffing the intestinal cavity without easily seeing the opening of the intestinal cavity. (3) Anal sinusitis Sinusitis, also known as anal saphenous fossa, is an inflammatory lesion of the anal saphenous fossa at the dentate line of the anus. The clinical manifestations are urgency, incomplete defecation, anal pain, anal burning and anal swelling, anal sphincter tension, anal sinus and anal papilla tenderness, anal sinus and anal papilla congestion and redness seen under anoscopy. (4) Proctal protrusion Proctal protrusion is the protrusion of the anterior rectal wall, also known as anterior rectal bulge. It is one of the exit obstruction syndromes, in which the rectovaginal wall of the patient’s rectovaginal septum is weak and protrudes into the vagina. The clinical manifestations of this disease are difficulty in passing stool, increased frequency of stool, feeling of incomplete defecation and anal swelling. On rectal palpation, a round or oval area of weakness in the anterior rectal wall at the upper end of the anal canal can be palpated towards the vagina, and the protrusion is more obvious when feces is passed by force. The anterior wall of the rectum can be seen to protrude forward on fecal imaging, making it difficult for the barium to pass through the anal canal. The morphology of the anterior protrusion is mostly pouch-like; if combined with the lesion of the anterior puborectal muscle, it mostly shows the goose sign. (5) Perineal descent syndrome The perineal descent syndrome refers to the patient’s anal canal being located at a lower level in the quiet state, while during forceful fecal evacuation, the perineum descends below the level of the sciatic node. The clinical manifestations of this disease include a feeling of incomplete defecation, difficulty in defecation, anal canal struggle during defecation, pain in the perineum, and sometimes mucous and bloody stools and prolapse of mucous membrane and hemorrhoid nucleus outside the anus. On visual examination, the anal canal may be located in a normal position or 1.0 cm below the bony outlet of the pelvis, but when the patient is asked to squat, the anal canal may drop more than 2.0 cm or even exceed the level of the sciatic tuberosity. On rectal examination, the dilatation force of the anal canal at rest was reduced, and when the patient was instructed to do random contractions, the contraction force of the anal canal was significantly weakened. On anoscopy, the mucous membrane of the anterior rectal wall was seen to accumulate and block the mirror end. Anal canal manometry, the resting pressure and maximum systolic pressure of the anal canal can be reduced. The static phase of defecography shows mild perineal descent and a small amount of anterior rectal wall bulge; the force discharge phase shows a 3.5 cm descent of the entire perineum, especially in the posterior part. In addition to showing abnormally low pelvic floor position, some other lesions can be found, such as anterior rectal bulge, prolapse, etc. (6) Puborectal muscle syndrome Puborectal muscle syndrome is a fecal disorder characterized by spastic hypertrophy of the puborectal muscle, resulting in obstruction at the outlet of the pelvic floor. The histological changes are hypertrophy of the puborectalis muscle fibers. The clinical manifestations of this disease include progressive worsening difficulty in fecal evacuation, prolonged fecal evacuation, thinning of stool, incomplete fecal evacuation, pain in the anal or sacral region during fecal evacuation, and nervousness in some patients. Rectal palpation shows increased anal canal tone, prolonged anal canal, and marked hypertrophy and tenderness of the puborectal muscle, sometimes with sharp edges. The anal canal pressure measurement showed that the constriction pressure was increased, suggesting an abnormal fecal reflex curve, and the functional length of the sphincter muscle was significantly increased, up to 5-6 cm. The balloon forcing out test showed that 50 ml or 100 ml of balloon could not be expelled from the rectum, but normally it was expelled within 5 min. Pelvic floor electromyography showed significant paradoxical electromyographic activity of the puborectalis muscle. Colonic transport function examination showed retention in the rectum. The fecal imaging showed that all measurements were normal, but the anal canal did not open during fecal evacuation, and there was a “loft sign” at rest and during forceful evacuation. (7) Pelvic floor spasm syndrome Pelvic floor spasm syndrome is a functional disease in which the muscles of the pelvic floor contract and cannot be coordinated to relax during forceful defecation, resulting in difficulty in defecation. The clinical manifestations of this disease include irregular bowel movements, small number of bowel movements, bowel movements every 2 to 3 days, difficulty in passing stool, feeling of incomplete defecation, and anal pain. On rectal examination, the anal sphincter is tense, the anal canal is hard behind the rectal ring, and there is tenderness. Defecography showed no increase in the anorectal angle during defecation, deepening of the puborectal muscle indentation, poor opening of the anal canal, and no downward shift of the pelvic floor level. Anal manometry showed normal resting and systolic anal canal pressure, and recto-anal inhibition reflex was present. The pelvic floor electromyography showed slight electrical activity at rest and a sharp increase in electrical activity during defecation. (8) Internal sphincter failure Internal sphincter failure refers to a disorder of anorectal function in which the internal anal sphincter cannot be diaped in a coordinated manner during defecation, causing defecation disorders. The clinical manifestations of this disease include painless difficulty in defecation, indifferent or no bowel movement, dry stool, or discomfort of perineal swelling, and sometimes incomplete defecation. Rectal examination shows increased elasticity of the internal anal sphincter, tenderness, increased pressure in the anal canal, or even difficulty in entering the anal canal with the fingertip, and more stool in the rectum. The fecal imaging showed that except for the perineal descent in the force discharge phase, all other measurements were within the normal range, and the anal canal was not open, the rectal neck was symmetrically cystic dilated, and the anorectal junction was “carrot root”-like change, and the rectum was obviously dilated in the resting phase, and the barium could not be completely expelled. The resting pressure was significantly higher than normal, and the amplitude of the inhibition reflex of the endorectal sphincter decreased, which showed that when the rectum was dilated by the balloon, the pressure of the anal canal did not decrease significantly or increased. The patient’s maximum tolerated rectal volume was significantly elevated. Pelvic floor electromyography showing the firing frequency and firing interval of the internal sphincter, and the presence or absence of electrical rhythm inhibition during rectal dilatation are important for the diagnosis of this disease.