Rectal examination is one of the “four examinations” in Traditional Chinese Medicine (TCM), which includes observation, inquiry, auscultation, and palpation. Traditional TCM rectal examination consists of pulse diagnosis and palpation, with pulse diagnosis focusing on the cun kou pulse, while palpation primarily examines the skin, limbs, chest, abdomen, and perianal area. There is no record in ancient or modern TCM literature regarding rectal palpation. The author has realized that the information obtained from rectal examination can provide a basis for TCM differentiation, and rectal examination can serve as a supplementary method in TCM diagnosis, offering significant guidance for treatment differentiation.
To distinguish it from the Western medical practice of rectal examination, which solely checks for pathological changes, the author refers to the rectal examination used for guiding TCM differentiation as “rectal examination” (zhichang qie zhen). Here, I will introduce my understanding and experience of “rectal examination” to spark discussion.
1. Basic Content of Rectal Examination
During rectal examination, attention should be paid to collecting relevant information from the rectal mucosa, rectal wall, internal and external masses, rectal cavity, sphincter, surrounding organs, temperature, sensitivity, and pain.
1. Rectal Mucosa
(1) Smoothness of the mucosal surface
The normal rectal mucosa is thin and smooth, with uniform thickness. If the mucosa is rough, it usually indicates inflammation; if it is thickened or uneven, Crohn’s disease should be considered. If there are soft masses on the mucosal surface, rectal polyps or even rectal cancer should be considered.
Excessively smooth rectal mucosa is often due to an abundance of secretions such as mucus in the rectal cavity, which is commonly caused by inflammatory bowel disease.
Patients with stubborn constipation often have a sticky rectal mucosa, where the examining finger feels sticky and resistant. These patients often have feces adhering to the rectal wall, and the finger cots may be covered with a glue-like fecal or mucous substance that is difficult to remove. Although the stool of these patients is not hard, they still experience difficulty in defecation.
(2) Relaxation of the mucosa
The normal rectal mucosa is not relaxed or has slight relaxation.
Some patients exhibit relaxation of the mucosa, characterized by increased mobility or folding and accumulation of the mucosa. These patients often experience a sensation of incomplete evacuation or difficulty in defecation, but may not have obvious discomfort symptoms. Therefore, relaxation of the rectal mucosa does not necessarily lead to difficulty in defecation.
In constipated patients, relaxation of the mucosa may be due to prolonged straining during defecation or congenital abnormalities.
2. Rectal Wall
(1) Thickness and elasticity
The rectal wall should have moderate thickness, with a certain degree of relaxation and elasticity, especially in the rectal ampulla and the anterior wall of the rectum in females (i.e., the rectovaginal septum).
In routine rectal examinations of patients in the proctology clinic, it is found that the majority of adult females have a relatively relaxed rectovaginal septum, particularly in those who have given birth or are elderly.Studies show that in healthy individuals, mild rectal prolapse is common; only 23% to 70% of those with rectal prolapse experience difficulty in defecation..
The author has observed that most women have a rectal anterior wall that protrudes more than one finger’s breadth, and most do not experience difficulty in defecation.When the rectovaginal septum sinks more than one and a half finger breadths (approximately 3 cm) during rectal examination, and assistance is needed for defecation, this anterior protrusion of the rectovaginal septum has clinical significance.
(2) Masses within the rectal wall
Submucosal or intramural masses in the rectum are commonly caused by residual induration after sclerotherapy for internal hemorrhoids, inflammation or thrombosis of internal hemorrhoids, post-electrocautery treatment of internal hemorrhoids, submucosal abscesses, or high interstitial abscesses. Occasionally, rectal stromal tumors, rectal leiomyomas, or rhabdomyomas, and endometriosis may be found. These masses have certain clinical morphological characteristics and require correlation with medical history and pathological examinations for accurate diagnosis. Masses within the rectal wall are often accompanied by a sensation of anal heaviness, urgency, or difficulty in defecation.
3. Rectal Cavity
(1) Size of the rectal cavity
The normal rectal cavity has an appropriate space and does not closely adhere to the opposite wall. The rectal wall is often seen in thin individuals, generally without discomfort.
Sometimes, patients may have no space in the middle of the rectal cavity, with the opposite wall being tight, and even during examination, there is a feeling of pressure from all sides. These patients often find defecation laborious, experiencing difficulty or a sensation of incomplete evacuation. The author has found that the degree of difficulty in defecation correlates positively with the pressure felt by the examining finger during rectal examination; the greater the pressure, the more difficult the defecation.
(2) Residual feces in the cavity
According to the author’s statistics, about 31% of patients in the proctology clinic have residual feces found during rectal examination, with approximately 50% among constipated patients. Patients reporting granular stools or alternating hard and soft stools have a higher rate of residual feces; those with frequent urges to defecate usually have a slightly lower rate of residual feces.
The absence of residual feces in the rectal cavity indicates good rectal sensation and emptying, generally without any obstructive factors present. In constipated patients, attention should be focused on possible slow transit issues in the colon.
When there is a significant amount of residual feces in the rectal cavity, but the patient does not have a strong urge to defecate, it suggests a dull defecation sensation, indicating potential issues with rectal sensory function or neural regulation. This is often related to poor defecation habits, such as frequently holding in bowel movements (e.g., sleeping in, work stress).
4. Sphincter and Adjacent Organs
(1) Sphincter
The normal rectal and anal sphincter muscles should have appropriate tension and relaxation.
Some individuals have hypertrophied anal and rectal muscles, with a feeling of tightness, and when instructed to relax, they cannot effectively do so, or they may even tighten further, indicating a functional abnormality of the anal sphincter.
If the anal and rectal muscles and pelvic floor muscles are weak or relaxed, the distance between the anal opening and the two ischial tuberosities may be small or even aligned, indicating pelvic floor muscle relaxation or weakness in the muscles related to defecation. This condition is more common in elderly patients or those with extreme physical weakness.
(2) Prostate or uterus
In males, prostate enlargement or tumors may sometimes affect the sensation or process of defecation. If prostate enlargement or masses are found during rectal examination, constipation may be related to prostate disease.
In females, a retroverted uterus or enlarged uterine fibroids or adnexal tumors compressing the rectum can lead to difficulty in defecation or a sensation of residual feces. If a retroverted or large uterus is palpated during rectal examination, consideration should be given to uterine retroversion or gynecological tumors.
(3) Coccyx
Occasionally, patients with coccyx fractures may have the coccyx bent forward at a right or acute angle, pressing against the anterior tissues, which can cause anal heaviness and difficulty in defecation, usually with tenderness at the coccyx or sacrococcygeal joint.
5. Sensation
(1) Sensitivity
If patients are sensitive to the touch during rectal examination, involuntarily twisting their bodies or tightening their buttock muscles and anal canal, these patients generally have good rectal emptying, with little residual feces, but may have a strong urge to defecate or a sensation of residual feces. Common causes include rectal inflammation, ulcers, or high individual sensitivity. If patients are dull to the touch during rectal examination, appearing relaxed, and even when a large amount of feces is palpated in the rectal cavity, they do not have a defecation urge, it suggests potential issues with rectal sensation or neural regulation.
(2) Pain
During normal anal and rectal examination, anal pain should first rule out anal sinusitis and anal fissures. Additionally, some patients with sacral nerve syndrome may experience pain on one side of the rectum or at specific points, and some patients post-PPH surgery may have significant tenderness at the anastomosis site, while others may have tenderness at the fundus of the uterus.
(3) Temperature
The temperature within the rectal cavity usually remains constant at around 37.0℃, but some patients may have significantly higher or lower temperatures in the rectal cavity. Elevated temperature is common in fever, perianal abscess, constipation, rectal inflammation, etc. Low temperature is often seen in patients with a cold and deficient constitution.
2. Application of Rectal Examination in the Differentiation of Constipation
Rectal examination can provide extremely valuable evidence for the differentiation and treatment of constipation, especially when there are no obvious systemic symptoms and limited information from the “four examinations”. When there are many systemic symptoms and the condition is complex, it can also provide primary evidence for differentiation.
The characteristics of rectal examination for common types of constipation are as follows.
(1) Spleen Qi Deficiency with Damp-Heat
During examination, the finger feels significant pressure from surrounding tissues, the rectal cavity is not empty, finger movement is sticky, and the finger cots are often covered with a viscous gel-like substance or a mixture of feces and mucus, with a foul odor.
This is often seen in patients with chronic colitis. It often occurs after alcohol consumption or spicy food, with patients experiencing soft and sticky stools that are difficult to pass, or stools with red and white mucus on the surface, followed by a sensation of heaviness or urgency, abdominal discomfort, or bloating, halitosis, frequent oral ulcers, dry mouth with a desire to drink or little fluid intake, frequent foul-smelling gas, and some patients may have moist and unclean perianal areas, often accompanied by perianal itching. The tongue is pale, the body is often enlarged with teeth marks, the tongue coating is normal or slightly greasy, or yellow and greasy at the root, and the pulse is slippery or weak.
(2) Yin Deficiency with Dry-Heat
During examination, the rectal cavity is empty, the rectal wall is dry and slippery, with either a small or large amount of hard feces. Some patients may have elevated temperature in the rectal cavity.
This is often seen in elderly or weak individuals or young adults who have taken laxatives for a long time. Symptoms include hard stools that are difficult to pass, occurring every few days, dry mouth with a desire to drink, abdominal bloating or discomfort, mental fatigue, or night sweats, irritability, a dry red tongue with little moisture or cracks, thin coating, and a thin or rapid pulse.
(3) Dry-Heat Accumulation
During examination, the rectal wall mucosa is dry and rough, with feces often retained in the cavity, and some patients may have elevated temperature in the rectal cavity.
This is often seen in young adults. Symptoms include hard stools that are difficult to pass, occurring every few days, abdominal bloating or fullness, dry mouth and thirst, flushed face, red urine, a red tongue with prickles, yellow and dry coating, and a rapid or slippery pulse.
(4) Yang Deficiency with Constipation
During rectal examination, there is often a significant amount of residual feces in the rectal cavity, mostly soft stools, and the rectal wall is relatively smooth. Male patients may have prostate enlargement. The temperature in the rectal cavity is often low.
This is often seen in elderly or weak individuals, and also in young adults with insufficient constitution, as well as women who have had multiple miscarriages. Symptoms include difficult and hard stools, occurring every few days, or a fear of cold, weakness in the lower back and knees, abdominal cold pain, frequent nighttime urination, pale complexion, a pale tongue with thin coating, and a weak pulse.
(5) Qi Deficiency with Qi Stagnation
During examination, the rectal mucosa is relatively relaxed and accumulated, with a small amount of soft or loose stools in the rectal cavity, and the examining finger feels significant pressure from surrounding tissues. Female patients often have a relaxed rectovaginal septum or a retroverted uterus.
This is often seen in weak or elderly female patients. Symptoms include difficulty in defecation, a sensation of anal heaviness or urgency, stools that are either soft or alternating between hard and soft, difficult to pass or incomplete, often with mucus in the stool, and symptoms of fatigue, poor appetite, and sweating upon exertion. Patients may appear thin, with a sallow complexion, low voice, and weak pulse.
In summary, the information obtained from rectal examination is individualized and specific, which can provide significant guidance for differentiation and treatment without the need for instrumental detection, especially in conditions with limited examination equipment.
Welcome to follow! Long press the QR code in the image above to follow. If you are my medical colleagues, please indicate your unit, department, and name when following, and I will mark you as a colleague so that you can see my professional WeChat (some professional content and images are not suitable for general readers).