rectosigmoid junction скачать в хорошем качестве

rectosigmoid junction

(RSJ) The limit between the sigmoid colon and the rectum. Therefore, it is the end of the sigmoid colon or the beginning of the rectum. This part of the colon is intraperitoneal and connected to the pelvic wall by the sigmoid mesocolon. In adults, it locates about 12 cm from the anus and at the level of the 3rd sacral vertebra or the sacral promontory. It is a critical area for ischemia, supplied by the sigmoidea ima artery, the lowest sigmoid artery, which forms the distal end of the marginal artery of Drummond by linking with the superior rectal artery. From the distal transverse colon to the rectosigmoid junction receive arterial supply from the inferior mesenteric artery. The sigmoid colon (pelvic colon) is innervated by the pelvic splanchnic nerves as the primary source for parasympathetic innervation and by the lumbar splanchnic nerves for sympathetic innervation via the inferior mesenteric ganglion. It shows an increased activity in patients with constipation, causing a physiologic obstruction to the passage of stool into the rectum. In contrast, it demonstrates markedly decreased activity in patients with diarrhea, thereby providing unobstructed access of the feces to the rectum. A physiological sphincter exists at the rectosigmoid junction as the rectosigmoid sphincter, that might govern the passage of stool from the sigmoid colon into the rectum, relaxing on sigmoid colon contraction and contracting on rectal contraction. It seems to be the site of a "pacemaker" triggering the pacesetter potentials that pace the action potentials which initiate the rectal contractile activity. Upon receiving electric pulsing, the rectal pressure increased, rectal neck pressure decreased, and the feces is expelled. An artificial colonic pacemaker could be effective in the treatment of idiopathic constipation and fecal incontinence.