Where is the female rectum located?

The duodenum of the human body is actually just inside the anus. It is connected to the anus, and above it is part of the sigmoid colon. It is the last section of the intestine, and because it is relatively vertical downward, it is called the duodenum. The relationship between the duodenum and the pelvic organs is different in men and women. In front of the duodenum of men are the duodenal fossa, seminal vesicle, ejaculatory duct ampulla, prostate, and pelvic urethra; while in women, there are the uterus, vagina, posterior vaginal fornix, duodenal fossa, and uterine vaginal septum. Therefore, during clinical digital anal examination, the male prostate and seminal vesicles or uterus and vagina can be palpated through the anus.

Its course is not straight but has several bends. It has three transverse walls, two on the left and one on the right, with different heights. Viewed from the bottom, the three walls overlap each other, surrounding the duodenum and carrying fecal stones.

The section of the duodenum near the anus expands to become the duodenal ampulla, which contains 6 to 10 vertical wrinkled walls called anal columns, and there is a venous plexus above the anal columns. The duodenum finally reaches the anus. The anus opening has external anus opening extension and internal anus opening extension. The anal dilatation is a voluntary muscle and belongs to the perineal muscles. The internal dilatation of the anus is formed by the thickening of the intestinal circular muscle and is a smooth muscle. Its function is to completely eliminate waste remaining in the anus when defecation is about to be completed.

The duodenum refers to a section of the intestine that starts from the sigmoid colon just in front of the third intervertebral disc, slides down along the front of the sacrum and coccygeal vertebrae, crosses the pelvic diaphragm and transitions to the anal canal. The duodenum is a section of the digestive tract located below the pelvis, with a total length of 10 to 14 cm. The duodenum is curved, forming two significant bends in the sagittal plane, namely the sacral duodenal flexure and the duodenoperineal flexure. There are also three bends protruding to the side in the coronal plane, but they are unstable. Generally, the large one in the middle protrudes to the left, and the two on the left and right protrude to the right. When clinically performing proctoscopy and sigmoidoscopy, attention should be paid to these bending positions to avoid damaging the intestinal cavity.