Finger touching the anus, also known as anal finger examination, is a simple, easy and important anorectal examination method, because many anorectal diseases can be detected early by anal finger examination alone, for example, 80% of rectal cancer can be detected during anal finger examination. It is worth noting that about 85% of the cases of delayed diagnosis of rectal cancer are due to the failure to perform anorectal examination, and some of them even lose the time for surgery, which is worth the attention and vigilance of both doctors and patients. The examination method is as follows: the examiner wears a finger sleeve on the right index finger and applies lubricant (commonly soap solution, liquid paraffin or petroleum jelly) to facilitate its insertion into the anus and to reduce the patient’s discomfort. If there is redness, swelling, tenderness, or hardness around the anal verge, it often indicates a perianal abscess; if there is tenderness in the front and back, it often indicates a possible anal fissure, and the anus can be further opened to see if there is a fissure in the anal canal; if there is an ulcerated opening outside the anal verge with a subcutaneous strip leading into the anus, it is often an anal fistula. After the examination around the anal verge, the right index finger should be gently massaged into the anal verge, and the patient should be asked to take a deep breath to reduce the abdominal pressure and relax the sphincter, and then the index finger should be slowly inserted into the rectum; if the finger is suddenly inserted into the anus, the sphincter will spasm due to the sudden stimulation, which will not only be difficult to insert but also painful. The first thing to do is to check the tightness of the anal sphincter and the rectal ring of the anal canal, which is composed of the upper edge of the internal and external sphincter and the puborectal muscle, around the junction of the anal canal and rectum, the internal and external sphincter is in the shape of a ring, while the puborectal muscle exists only in the back and on both sides, so when the anal finger is examined, it is touched in the back and on both sides of the anal canal. And it is not easy to touch in the front of the anal canal. The anal sphincter and the anal canal rectal ring can reach into the anus smoothly when they are normal, if the index finger has difficulty passing or cannot pass it means that the anus has different degrees of stenosis, and if the anal sphincter is too loose and weak, there may be anal incontinence; 2. Check the anterior and posterior walls of the anal canal rectum and its surrounding for tenderness, pulsation and masses, and you should pay attention to the size, hardness and mobility. For the masses in higher position, the anorectal examination can be done in squatting position or lithotomy position, which can make the tumor move down and can find the rectal cancer in higher parts. If necessary, double diagnosis of rectum and abdomen or double diagnosis of rectum and vagina can be done, which can provide valuable information on the scope of cancer invasion; 3. In the anterior rectal wall, men can touch the prostate gland and women can touch the cervix, which should not be mistaken for pathological mass; 4. After the finger is withdrawn after examination, it should be seen whether the finger sleeve is stained with blood or mucus, and smear examination should be done if necessary. During the anal finger examination, several common anal canal rectal lesions can be palpated: 1, rectal cancer: uneven hard masses can be felt on the intestinal wall, its surface can have ulcers, the intestinal cavity is often narrow, and the finger sleeve is often stained with pus, blood and mucus. 2, rectal polyps: soft and pushable masses can be felt, often stained with blood on the finger sleeve. The most important thing is that you can feel the hemorrhoids, and even if you feel them, you can’t tell their size and number, but if there is a thrombosis, you can feel a smooth hard knot. 4, anal fistula: you can feel the cords, and sometimes you can find small hard knots or depressions in the inner mouth of the fistula. 5.Perianal rectal abscess: pelvic rectal gap abscess and posterior rectal gap abscess can be palpated in the rectum as a painful mass with a smooth surface. Other interstitial abscesses can be examined by double-finger palpation with the thumb and index finger, i.e. the index finger is placed in the rectum and the thumb is placed on the perianal skin, and palpation with the thumb and index finger can reveal deep anterior and deep posterior interstitial abscesses of the anal canal, abscesses of the scirorectal space or perianal abscesses. 6. anal papilloma: a medium-textured and pushable, long-tipped swelling with a clean finger sleeve can be palpated. Because finger examination has such an important role, all patients who visit the anorectal department for the first time will be touched by the doctor, and will be touched more deeply and carefully so as not to miss the misdiagnosis, the patient may feel more uncomfortable, but please be sure to cooperate. Patients who are not aware of the importance of the finger examination often do not cooperate, but also complain that they will never do this examination again. Happily, in recent years, more and more patients are aware of this and often ask for finger examinations on their own initiative, and will come regularly.