What Is the Rectum?

Rectum: The last section of the intestine, connected to the sigmoid colon at the top, and connected to the anus at the bottom.

Rectum: The last section of the intestine, connected to the sigmoid colon at the top, and connected to the anus at the bottom.

Chinese name

rectum

Foreign name

rectum

Pinyin

Zhi Chang

Rectal physiology

The rectum is located in the pelvis and is the end of the large intestine. A total length of 12 to 15 cm, descending along the front of the sacrum and coccyx, piercing the pelvis, and terminating the anus. The rectum above the pelvic ridge is called the pelvis, and the following parts are called the anus and anal canal. The lower end of the pelvis is sometimes fusiform, called the rectum ampulla. The rectum has two bends in the anterior-posterior direction. The upper curvature is called rectal curvature, which is convex to the back, and the lower curvature is convex to the front, which is called rectal perineal curvature. When performing sigmoidoscopy, the two bends must be inserted slowly to avoid damaging the intestinal wall. The bladder, seminal vesicles, and prostate are located in front of the rectum in men, and the uterus and vagina are located in front of the rectum in women. Therefore, these organs can be examined transrectally.

Rectal anatomy

The rectum is the last section of the digestive tract and is located in the pelvic cavity. It is about 15-20 cm long. Its stroke is not straight and there are several flexions. It has three horizontal folds, two of which are on the left and one on the right. Seen from below, the three folds overlap each other, circum around the rectum, supporting the feces.

The section of the rectum near the anus is enlarged to form the ampulla of the rectum, which contains 6 to 10 anal columns with vertical folds and venous plexus above the anal column. The rectum is finally anal. There are external anal sphincter and internal anal sphincter. The external anal sphincter is a voluntary muscle and belongs to the perineal muscle. The internal anal sphincter is thickened by the intestinal ring muscle and belongs to smooth muscle. Its role is to completely remove the waste remaining in the anal canal at the end of stool.

The rectum refers to the rectum from the front of the third lumbar vertebra, starting from the sigmoid colon, descending along the iliac crest and the tailbone, and passing through the pelvic ridge to the anal canal. The rectum is a section of the digestive tract located in the lower part of the pelvic cavity, with a total length of 10 to 14 cm. The rectum is not straight, and two distinct curvatures are formed on the sagittal plane, namely, rectal curvature and rectal perineal curvature. On the coronal plane, there are also three bends protruding sideways, but they are not constant. Generally, the larger one is convex to the left, and the upper and lower two are convex to the right. When performing rectal and sigmoidoscopy clinically, attention should be paid to these curved parts to avoid damaging the intestinal wall.

Rectal and rectal-related diseases and their clinical treatment

1. Urethral rectal fistula: The male fistula is located in the urethral membrane, and is most often complicated by high anal atresia. Therefore, when dealing with anal atresia, it can cause urethral stricture, or even cut off the urethra, and when some ligated fistulas are too far away from the urethra, there is a diverticulum-like cavity, which can cause secondary infection or stones due to urine retention. When urethral rectal fistula, some children may have lower urinary tract infections. If there is no upper urinary tract malformation and bladder ureteral reflux, the harm is not great. Anal outflow of urine and urethral discharge of feces are the main symptoms of urethral rectal fistula. The anus is diagnosed at the anterior fistula of the rectum about 2 cm from the anus and can touch the depressed fistula. The treatment is a transoccipital incision, a rectal resection, and a fistula closure and temporary urinary regurgitation, such as a cystostomy.

2. Appendical fistula:

3. Anorectal fistula:

Anorectal fistula, referred to as anal fistula, is a fistula that occurs near the anus and below the rectum. One end of the fistula enters the anus or rectum, and the other end of the fistula passes outside the anus or other areas. The fistula in the skin is called the outer mouth, and the fistula in the rectum is called the inner mouth. The disease is more common, although the disease is not related to age, but mostly middle-aged people aged 30 to 40.

[Cause] The cause of anal fistula is often punctured around the anorectal abscess, or cut open by surgery. After the pus is discharged, the pus cavity shrinks, but does not close, forming a fistula.

[Medical manifestation]

(1) There are three manifestations of anal fistula, namely pus, pain and itching.

Pus is the primary symptom of anal fistula. Panties are often wet and contaminated with pus. The amount of pus varies depending on the length of the fistula. There is more pus in the new fistula, thick yellow pus, and smelly. Chronic fistula pus is less and sometimes absent. The pus is white and thin like water. A sudden increase in pus indicates a new fistula. Sometimes the fistula near the anus can be temporarily closed without pus, but soon swelling and pain appear locally, the closed fistula ruptures again, and pus flows out. Examination revealed a depression on the skin near the anus, or a papillary protrusion, or a bulge of granulation tissue. There is a small amount of pus, or bloody purulent discharge overflows.

(2) Anal fistula is generally not painful. If pain appears, it indicates inflammation.

(3) Itching is caused by pus or secretions that stimulate the skin around the anus, often with eczema.

[Treatment method] The only treatment for anal fistula is surgical treatment, which removes or cuts the anal fistula, or hangs the anus.

[Family care] Anal fistula should be treated with surgery, pay attention to rest after surgery, keep the stool open, and use a potassium permanganate warm bath to wash it daily to maintain anal hygiene. Change the dressing in time to prevent infection.

[Doctor cautions] Anal fistula should be removed as early as possible, and conservative treatment should not be used to prevent the disease from spreading.

[When to go to the hospital] When you find an anal fistula, go to the hospital for surgical removal as soon as possible.

[Prevention method] Pay attention to the hygiene of the anus and vulva, and timely treatment of inflammatory lesions around the anus can prevent the disease.