[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Pelvis](https://durgical.com/en/anatomy/region/pelvis/) › Rectum [Digestive system](https://durgical.com/en/anatomy/system/digestive-system/) · [Pelvis](https://durgical.com/en/anatomy/region/pelvis/) # Rectum The rectum is the last part of the large bowel, in front of the sacrum and behind the vagina and uterus; it stores stool until the bowel empties. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=pelvis&select=rectum&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The last part of the large intestine, behind the vagina and uterus. ## What it does Stores stool until it is time to empty the bowel. ## Key points - Usually three transverse rectal folds (valves of Houston): upper and lower on the left, middle on the right; the middle fold lies at about the level of the anterior peritoneal reflection - The mesorectum (fat with the superior rectal vessels and nodes) is wrapped in the mesorectal fascia; total mesorectal excision removes the rectum inside this intact envelope for rectal cancer - Front relations differ by sex: in women the rectouterine pouch and [vagina](https://durgical.com/en/anatomy/vagina/); in men the rectovesical pouch, seminal vesicles and prostate, behind the rectoprostatic (Denonvilliers) fascia - Lymph from the upper rectum follows the superior rectal vessels to the inferior mesenteric nodes; the lower rectum also drains sideways to the internal iliac nodes ## Key facts **Where** From S3 to anorectal junction at pelvic floor, about 12–15 cm; peritoneum covers upper third front and sides, middle third front only; no taeniae **Blood supply** Superior rectal (IMA), middle rectal (internal iliac) and inferior rectal (internal pudendal) arteries **Nerve** Sympathetic: lumbar splanchnics via hypogastric plexuses; parasympathetic: pelvic [splanchnic nerves](https://durgical.com/en/anatomy/greater-thoracic-splanchnic-nerve/) (S2–S4), also carry stretch sensation **Function** Stores stool in the ampulla; distension triggers the defecation reflex ## Relations **In front** Women: [rectouterine pouch](https://durgical.com/en/anatomy/rectouterine-pouch/) with loops of small bowel, then the posterior vaginal wall across the rectovaginal septum. Men: [rectovesical pouch](https://durgical.com/en/anatomy/rectovesical-pouch/), then the bladder base, [seminal vesicles](https://durgical.com/en/anatomy/seminal-gland/), ampullae of the vas deferens and [prostate](https://durgical.com/en/anatomy/prostate/) **Behind** [Sacrum](https://durgical.com/en/anatomy/sacrum/) and [coccyx](https://durgical.com/en/anatomy/coccyx/), the presacral fascia with the presacral venous plexus, median sacral vessels, [sacral nodes](https://durgical.com/en/anatomy/lateral-sacral-nodes/) and sacral nerve roots **Lateral** Above, the pararectal fossae of [peritoneum](https://durgical.com/en/anatomy/peritoneum/); below, the [levator ani](https://durgical.com/en/anatomy/levator-ani/), the lateral ligaments with the middle rectal vessels, and the [inferior hypogastric plexus](https://durgical.com/en/anatomy/inferior-hypogastric-plexus/) **Above** Rectosigmoid junction, where the taeniae of the [sigmoid colon](https://durgical.com/en/anatomy/sigmoid-colon/) spread into a continuous muscle coat **Below** Anorectal junction, pulled forward by the [puborectalis](https://durgical.com/en/anatomy/puborectalis/), continuing as the [anal canal](https://durgical.com/en/anatomy/anal-canal/) ## How to find it On digital rectal examination the finger passes the anal canal into the lower rectum. Through the front wall it feels the [cervix](https://durgical.com/en/anatomy/cervix-of-uterus/) in women, and the prostate (sometimes the seminal vesicles) in men. Above, the rectouterine or rectovesical pouch may be tender (pelvic abscess, peritonitis) or hold a hard shelf (Blumer shelf from peritoneal metastases). ## On imaging Pelvic MRI stages rectal cancer: depth of spread through the wall, nodes, and the distance from the tumour to the mesorectal fascia (circumferential resection margin). Endorectal ultrasound suits early tumours; rigid sigmoidoscopy or MRI measures the height of a tumour from the anal verge. ## Common problems - Rectocele: it bulges into the back wall of the vagina. - Endometriosis can grow into its wall. ## Clinical notes - In total mesorectal excision the hypogastric nerves and pelvic splanchnic nerves lie just outside the mesorectal fascia; injuring them causes bladder and sexual dysfunction - Bleeding from the presacral venous plexus during rectal mobilisation can be severe and hard to control - Haemorrhoids are enlarged vascular cushions of the anal canal; rectal varices are portosystemic collaterals between the superior rectal (portal) and middle and inferior rectal (systemic) veins in portal hypertension: different conditions - Below the peritoneal reflection the rectum is extraperitoneal, so a full-thickness injury or perforation there does not open into the peritoneal cavity ## Anatomical variants - The number of transverse rectal folds varies, commonly from two to four; the middle fold is the most constant ## Development The urorectal septum divides the cloaca of the hindgut into the rectum and upper anal canal behind and the urogenital sinus in front; faulty division gives anorectal malformations, often with a fistula to the urinary tract or vagina. ## Related conditions - [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/) - [Ulcerative colitis](https://durgical.com/en/conditions/ulcerative-colitis/) - [Pelvic organ prolapse](https://durgical.com/en/conditions/pelvic-organ-prolapse/) - [Obstetric perineal tears and anal sphincter injury](https://durgical.com/en/conditions/obstetric-perineal-tears-and-anal-sphincter-injury/) - [Haemorrhoids](https://durgical.com/en/conditions/haemorrhoids/) - [Anorectal abscess and fistula](https://durgical.com/en/conditions/anorectal-abscess-and-fistula/) - [Rectal prolapse](https://durgical.com/en/conditions/rectal-prolapse/) - [Fecal incontinence](https://durgical.com/en/conditions/fecal-incontinence/) - [Lower gastrointestinal bleeding](https://durgical.com/en/conditions/lower-gastrointestinal-bleeding/) - [Colorectal polyps and hereditary polyposis syndromes (FAP, Lynch)](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/) - [Constipation and faecal impaction](https://durgical.com/en/conditions/constipation-and-faecal-impaction/) - [Bacterial infectious diarrhoea and dysentery](https://durgical.com/en/conditions/bacterial-infectious-diarrhoea-and-dysentery/) - [Hirschsprung disease](https://durgical.com/en/conditions/hirschsprung-disease/) - [Anorectal malformations (imperforate anus)](https://durgical.com/en/conditions/anorectal-malformations/) - [Functional constipation in children](https://durgical.com/en/conditions/functional-constipation-in-children/) ## Test yourself Think of the answer, then tap the question to see it. ## How are the transverse rectal folds (valves of Houston) arranged? Usually three: upper and lower on the left, middle on the right; the middle fold lies near the anterior peritoneal reflection. ## What does total mesorectal excision remove, and why is its plane important? The rectum within the intact mesorectal fascia; the hypogastric and pelvic splanchnic nerves lie just outside, and injury causes bladder and sexual dysfunction. ## Where does lymph from the upper and lower rectum drain? Upper: along the superior rectal vessels to inferior mesenteric nodes. Lower: also sideways to internal iliac nodes. ## How do rectal varices differ from haemorrhoids? Rectal varices are portosystemic collaterals in portal hypertension; haemorrhoids are enlarged vascular cushions of the anal canal. ## What is felt through the front wall of the rectum on digital examination in women and in men? The cervix in women; the prostate (sometimes the seminal vesicles) in men. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/rectum/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** rectum TA2 2998 **Official Spanish (DeCS)** Recto DeCS D012007 **English (TA2)** Rectum **Also called** intestinum rectum · intestinum terminale ## Related - [Rectouterine pouch](https://durgical.com/en/anatomy/rectouterine-pouch/) - [Internal iliac arteries](https://durgical.com/en/anatomy/internal-iliac-artery/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=12427); [Anatomy, Abdomen and Pelvis, Rectum](https://www.ncbi.nlm.nih.gov/books/NBK537245/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/rectum/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/rectum/