rectum

直腸 　 　

WordNet

1. the terminal section of the alimentary canal; from the sigmoid flexure to the anus
2. of or involving the rectum; "rectal cancer"

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1. 直腸
2. 直腸(rectum)の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/07/25 15:43:18」(JST)

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"Rectal" redirects here. For the route of administration, see Rectal administration. For the conic sections, see Latus rectum and Semi-latus rectum.

Human rectum
Drawing of human colon seen from front. The rectum consists of the distal portion of the colon, here coloured red
Anatomy of the anus and rectum
Details
Precursor	Hindgut
Artery	Superior rectal artery (first two-thirds of rectum), middle rectal artery (last third of rectum)
Vein	Superior rectal veins, middle rectal veins
Nerve	Inferior anal nerves, inferior mesenteric ganglia
Lymph	Inferior mesenteric lymph nodes, pararectal lymph nodes, internal iliac lymph nodes, Deep inguinal lymph nodes
Identifiers
Latin	Rectum
MeSH	A03.556.124.526.767
Dorlands /Elsevier	r_05/12697487
TA	A05.7.04.001
FMA	14544
Anatomical terminology

The lumen (inside) of a normal human rectum in a 70 year old seen at colonoscopy

Retroflexed view of the human rectum seen at colonoscopy showing anal verge

The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The human rectum is about 12 centimetres (4.7 in) long, and begins at the rectosigmoid junction (the end of the sigmoid colon), at the level of the third sacral vertebra or the sacral promontory depending upon what definition is used. Its caliber is similar to that of the sigmoid colon at its commencement, but it is dilated near its termination, forming the rectal ampulla. It terminates at the level of the anorectal ring (the level of the puborectalis sling) or the dentate line, again depending upon which definition is used. In humans, the rectum is followed by the anal canal, before the gastrointestinal tract terminates at the anal verge.

Structure

The rectum is a component of the lower gastrointestinal tract. The rectum is a continuation of the sigmoid colon, and connects to the anus. The rectum follows the shape of the sacrum, and ends in an expanded section called the rectal ampulla where feces are stored before their release via the anal canal. An ampulla is a cavity, or the dilated end of a duct, shaped like a Roman ampulla.

Unlike other portions of the colon, the rectum does not have taeniae coli.

The rectum connects with the sigmoid colon at the level of S3, and connects with the anal canal as it passes through the pelvic floor muscles.

Supports of the rectum include:

• Pelvic floor formed by levator ani muscles.
• Waldeyer's fascia
• Lateral ligaments of rectum which are formed by the condensation of pelvic fascia
• Rectovesical fascia of Denonvillers, which extends from rectum behind to the seminal vesicles and prostate in front.
• Pelvic peritoneum
• Perineal body

Function

The rectum acts as a temporary storage site for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the nervous system located in the rectal walls stimulate the desire to defecate. If the urge is not acted upon, the material in the rectum is often returned to the colon where more water is absorbed from the feces. If defecation is delayed for a prolonged period, constipation and hardened feces results.

When the rectum becomes full, the increase in intrarectal pressure forces the walls of the anal canal apart, allowing the fecal matter to enter the canal. The rectum shortens as material is forced into the anal canal and peristaltic waves propel the feces out of the rectum. The internal and external sphincter allow the feces to be passed by muscles pulling the anus up over the exiting feces.

Clinical significance

Examination

Main article: Rectal exam

For the diagnosis of certain ailments, a rectal exam may be done. These include faecal impaction, prostatic cancer and benign prostatic hypertrophy in men, faecal incontinence, and internal haemorrhoids.

A colonoscopy or sigmoidoscopy are forms of endoscopy that use a guided camera to view the rectum. These may have the ability to take biopsies if needed, and may be used to diagnose diseases such as cancer.

Body temperature can also be taken in the rectum. Rectal temperature can be taken by inserting a medical thermometer not more than 25 mm (1 inch) into the rectum via the anus. A mercury thermometer should be inserted for 3 to 5 minutes; a digital thermometer should remain inserted until it beeps. Normal rectal temperature generally ranges from 36 to 38 °C (96.8 to 100.4 °F) and is about 0.5 °C (1 °F) above oral (mouth) temperature and about 1 °C (2 °F) above axilla (armpit) temperature.

Pediatricians recommend that parents take infants' and toddlers' temperature in the rectum for two reasons:

1. Rectal temperature is the closest to core body temperature and in young children, accuracy is critical.
2. Younger children frequently do not cooperate when having their temperature taken by mouth (oral), which is recommended for children ages 6 and above as well as adults.

In recent years, the introduction of non-invasive temperature taking methods including tympanic (ear) and forehead thermometers, and changing attitudes on privacy and modesty have led some parents and doctors to discontinue taking rectal temperatures.

Route of administration

Main article: Suppository

The rectum may also be used as a site for the delivery of drugs, by way of a suppository.

Constipation

Main article: Constipation

One cause of constipation is faecal impaction in the rectum, in which a dry, hard stool forms. Manual evacuation is the use of a gloved finger to evacuate faeces from the rectum, and, after the application of stool softeners, is utilised in acute constipation. It is also in the long-term management of neurogenic bowel, seen most frequently in people with a spinal cord injury or multiple sclerosis. Digital rectal stimulation, the insertion of one finger into the rectum, may be used to induce peristalsis in patients whose own peristaltic reflex is inadequate to fully empty the rectum.

Diseases

• Proctitis is inflammation of the anus and the rectum.
• Rectal cancer, a subgroup of colorectal cancer specific to the rectum.
• Rectal prolapse, referring to the prolapse of the rectum into the anus or external area. This is commonly caused by a weakened pelvic floor after childbirth.

Other diseases

Other diseases of the rectum include:

• Ulcerative colitis, one form of inflammatory bowel disease that causes ulcers that affect the rectum. This may be episodic, over a person's lifetime. These may cause blood to be visible in the stool. As of 2014 the cause is unknown.
• In the context of mesenteric ischemia, the upper rectum is sometimes referred to as Sudak's point and is of clinical importance as a watershed region between the Inferior mesenteric artery circulation and the Internal iliac artery circulation via the Middle rectal artery, and thus prone to ischemia. Sudak's point is often referred to along with Griffith's point at the splenic flexure as a watershed region.

Society and culture

Sexual stimulation

See also: Anal sex

Due to the proximity of the anterior wall of the rectum to the vagina in females or to the prostate in males, and the shared nerves thereof, rectal stimulation or penetration can result in sexual arousal.

History

Etymology

English rectum is derived from the full Latin expression intestinum rectum. The English name straight gut truly expresses the literal meaning of this expression, as Latin rectum means straight, and intestinum means gut. This Latin expression is a translation of Ancient Greek ἀπευθυσμένον ἔντερον, derived from ἀπευθύνειν, to make straight, and ἔντερον, gut, attested in the writings of Greek physician Galen. During his anatomic investigations on animal corpses, Galen observed the rectum to be straight instead of curved as in humans. The expressions ἀπευθυσμένον ἔντερον and intestinum rectum are therefore not appropriate descriptions of the rectum in humans. Apeuthysmenon can be considered as Latinization of ἀπευθυσμένον ἔντερον and euthyenteron has a similar meaning (εὐθύς = straight).

Additional images

• Posterior aspect of rectum exposed by removing lower part of sacrum and coccyx

• Median sagittal section of male pelvis, showing arrangement of fasciae

• Arteries of the pelvis

• Median sagittal section of male pelvis

• Median sagittal section of female pelvis

• Sagittal section of the lower part of a female trunk, right segment

• Organs of the female reproductive system

• Cross-section microscopic shot of the rectal wall

• Section of mucous membrane of human rectum (60×)

• Dog Rectum cross-section (40×)

• Dog Rectum cross-section (400×)

See also

• Gastrointestinal tract
• Murphy drip
• Pectinate line
• Rectal prolapse
• Rectal thermometry

References

• Henry Gray: Anatomy of the human body (Bartleby.com; Great Books Online).
• Eldra P. Solomon, Richard R. Schmidt, and Peter J. Adragna: Human anatomy & physiology, 2nd ed. 1990 (Sunders College Publishing, Philadelphia). ISBN 0-03-011914-6.

External links

• Blue Histology
• Cross section image: pembody/body15a—Plastination Laboratory at the Medical University of Vienna
• Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
• Anatomy image:7808 at the SUNY Downstate Medical Center
• Anatomy photo:43:11-0101 at the SUNY Downstate Medical Center

UpToDate Contents

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• 1. Rectal cancer: Surgical principles
• 2. Klippel-Trenaunay syndrome: Clinical manifestations, diagnosis, and management
• 3. 痔核：臨床症状および診断 hemorrhoids clinical manifestations and diagnosis
• 4. Transanal endoscopic surgery (TES)
• 5. 経膣メッシュ曝露と骨盤手術後の疼痛のマネージメント management of transvaginal mesh exposure and pain following pelvic surgery

English Journal

• Continuous transanal decompression for infants with long- and total-type Hirschsprung's diseases as a bridge to curative surgery: a single-center experience.

• Mochizuki K1, Shinkai M2, Kitagawa N2, Take H2, Usui H2, Hosokawa T2, Yamoto K2.
• Surgical case reports.Surg Case Rep.2017 Dec;3(1):42. doi: 10.1186/s40792-017-0318-y. Epub 2017 Mar 10.
• PMID 28283986

• Transanal total mesorectal excision for a large leiomyosarcoma at the lower rectum: a case report and literature review.

• Hoshino N1, Hida K2, Kawada K2, Sakurai T3, Sakai Y2.
• Surgical case reports.Surg Case Rep.2017 Dec;3(1):13. doi: 10.1186/s40792-017-0289-z. Epub 2017 Jan 13.
• PMID 28092017

• Sphincter-saving resection by cluneal arched skin incision for a gastrointestinal stromal tumor (GIST) of the lower rectum: a case report.

• Tazawa H1, Hirata Y2, Kuga Y3, Nishida T4, Sakimoto H2,5.
• Surgical case reports.Surg Case Rep.2017 Dec;3(1):8. doi: 10.1186/s40792-016-0285-8. Epub 2017 Jan 5.
• PMID 28058590

Japanese Journal

• 腹腔鏡下大腸癌手術に日本内視鏡外科学会技術認定医の指導が及ぼす影響

• 滋賀医科大学雑誌 30(1), 18-21, 2017-02-01
• NAID 120005985377

• 臨床報告 診断に苦慮した膀胱癌術後再発による直腸輪状狭窄の1例

• 臨床外科 = Journal of clinical surgery 72(2), 228-231, 2017-02
• NAID 40021081752

• 腹部超音波断層像による小児直腸径の基準値

• 日本小児科学会雑誌 = The journal of the Japan Pediatric Society 121(1), 80-87, 2017-01
• NAID 40021068280

Related Links

• Rectumとは - goo Wikipedia (ウィキペディア)

One cause of constipation is faecal impaction in the rectum, in which a dry, hard stool forms. Manual evacuation is the use of a gloved finger to evacuate faeces from the rectum, and, after the application of stool softeners, is utilised in ...

• Rectum | definition of Rectum by Medical dictionary

rectum [rek´tum] the distal portion of the large intestine, beginning anterior to the third sacral vertebra as a continuation of the sigmoid and ending at the anal canal. The feces, the solid waste products of digestion, are formed in the ...

Related Pictures

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★リンクテーブル★

リンク元	「直腸」「rectal」
拡張検索	「colorectum」「solitary ulcer syndrome of rectum」

「直腸」

　　[★]

英

rectum (Z)

関

大腸

概念

• S状結腸に続き肛門に至る長さ約20cmの消化管
• 直腸結腸境界はS3椎体の高さ (M.229)
• 直腸は仙骨と尾骨のカーブに沿って走り、そこで後下方に曲がって肛門管になる (M.229)
• 3つの直腸横ヒダを持つ

直腸・肛門の区分

SSUR.559

• 直腸S状部：rectosigmoid,RS：岬角の高さより第2仙骨下縁の高さまで
• 上部直腸：rectum above the peritoneal reflection,Ra：第2仙骨下縁の高さから腹膜反転部まで
• 下部直腸：rectum below the peritoneal reflection,Rb：腹膜反転部から恥骨直腸筋付着部上縁まで
• 肛門管：proctos,P：恥骨直腸筋付着部上縁から肛門縁までの管状部
• 肛門周囲皮膚：external skin,E：肛門縁より外側の皮膚

「rectal」

　　[★]

• adj.

• 直腸の

関

rectum

　 　

「colorectum」

　　[★]

結腸直腸

関

colorectal

「solitary ulcer syndrome of rectum」

　　[★] 直腸孤在性潰瘍症候群