{"id":16391,"date":"2021-03-25T12:43:18","date_gmt":"2021-03-25T09:43:18","guid":{"rendered":"https:\/\/www.turkcerrahi.com\/?page_id=16391"},"modified":"2026-03-31T17:17:04","modified_gmt":"2026-03-31T14:17:04","slug":"colon-anatomy","status":"publish","type":"page","link":"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/colon-anatomy\/","title":{"rendered":"Anatomy of the Colon"},"content":{"rendered":"<div id=\"pl-16391\" class=\"panel-layout\"><div id=\"pg-16391-0\" class=\"panel-grid panel-no-style\"><div id=\"pgc-16391-0-0\" class=\"panel-grid-cell\"><div id=\"panel-16391-0-0-0\" class=\"so-panel widget widget_black-studio-tinymce widget_black_studio_tinymce panel-first-child panel-last-child\" data-index=\"0\"><div class=\"textwidget\"><figure id=\"attachment_15305\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-anatomy.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15305\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-anatomy-720x540.jpeg\" alt=\"Colon anatomy\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-anatomy-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-anatomy-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-anatomy.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Colon anatomy<\/figcaption><\/figure>\n\n<div class=\"panel-group\" id=\"accordionname79\"><div class=\"panel panel-default panel-even\"><div class=\"panel-heading\"><a class=\"accordion-toggle \" data-toggle=\"collapse\" data-parent=\"#accordionname79\" href=\"#collapse790\"><h5><i class=\"icon-minus primary-color\"><\/i><i class=\"icon-plus\"><\/i>CONTENTS<\/h5><\/a><\/div><div id=\"collapse790\" class=\"panel-collapse collapse in\"><div class=\"panel-body postclass\">\n<div class=\"kt-simple-box\" style=\"background-color:rgba(236, 246, 255, 1); min-height:1px; padding-top:15px; padding-bottom:15px; padding-left:15px; padding-right:15px; \"><div class=\"kt-simple-box-inner\">\n<ol>\n<li><a href=\"#introduction\">Introduction<\/a><\/li>\n<li><a href=\"#parts-of-the-large-intestine\">Parts of the Large Intestine<\/a><\/li>\n<li><a href=\"#difference-between-small-and-large-intestine\">Difference Between Small and Large Intestine<\/a><\/li>\n<li><a href=\"#peritoneal-relations-of-colon-and-taeniae-coli\">Peritoneal relations of colon and taeniae coli<\/a><\/li>\n<li><a href=\"#cecum\">Cecum<\/a>\n<ul>\n<li><a href=\"#ileocecal-valve-ileocecal-valve\">Ileocecal Valve (Ileocecal Valve)<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#appendix-appendix-vermiformis\">Appendix (Appendix Vermiformis)<\/a><\/li>\n<li><a href=\"#ascending-colon\">Ascending Colon<\/a><\/li>\n<li><a href=\"#transverse-colon\">Transverse Colon<\/a><\/li>\n<li><a href=\"#descending-colon\">Descending Colon<\/a><\/li>\n<li><a href=\"#sigmoid-colon\">Sigmoid Colon<\/a>\n<ul>\n<li><a href=\"#sigmoid-colon-mesentery\">Sigmoid Colon Mesentery<\/a><\/li>\n<li><a href=\"#rectosigmoid-junction\">Rectosigmoid Junction<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#rectum\">Rectum<\/a><\/li>\n<li><a href=\"#anal-canal\">Anal Canal<\/a>\n<ul>\n<li><a href=\"#surgical-anal-canal\">Surgical Anal Canal<\/a><\/li>\n<li><a href=\"#anatomical-anal-canal\">Anatomical Anal Canal<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#ligaments-of-the-colon\">Ligaments of the Colon<\/a><\/li>\n<li><a href=\"#arteries-of-the-colon\">Arteries of the Colon<\/a>\n<ul>\n<li><a href=\"#ileocolic-artery\">Ileocolic Artery<\/a><\/li>\n<li><a href=\"#right-colic-artery\">Right Colic Artery<\/a><\/li>\n<li><a href=\"#middle-colic-artery\">Middle Colic Artery<\/a><\/li>\n<li><a href=\"#left-colic-artery\">Left Colic Artery<\/a><\/li>\n<li><a href=\"#sigmoidal-arteries\">Sigmoidal Arteries<\/a><\/li>\n<li><a href=\"#rectal-arteries\">Rectal Arteries<\/a>\n<ul>\n<li><a href=\"#superior-rectal-hemorrhoidal-artery\">Superior Rectal (Hemorrhoidal) Artery<\/a><\/li>\n<li><a href=\"#middle-rectal-hemorrhoidal-artery\">Middle Rectal (Hemorrhoidal) Artery<\/a><\/li>\n<li><a href=\"#inferior-rectal-hemorrhoidal-artery\">Inferior Rectal (Hemorrhoidal) Artery<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#marginal-artery-of-drummond\">Marginal Artery of Drummond<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#veins-of-the-colon\">Veins of the Colon<\/a>\n<ul>\n<li><a href=\"#superior-mesenteric-vein\">Superior Mesenteric Vein<\/a><\/li>\n<li><a href=\"#inferior-mesenteric-vein\">Inferior Mesenteric Vein<\/a>\n<ul>\n<li><a href=\"#superior-rectal-hemorrhoidal-vein\">Superior Rectal (Hemorrhoidal) Vein<\/a><\/li>\n<li><a href=\"#middle-rectal-hemorrhoidal-vein\">Middle Rectal (Hemorrhoidal) Vein<\/a><\/li>\n<li><a href=\"#inferior-rectal-hemorrhoidal-vein\">Inferior Rectal (Hemorrhoidal) Vein<\/a><\/li>\n<li><a href=\"#rectal-venous-plexus-hemorrhoidal-plexus\">Rectal Venous Plexus (Hemorrhoidal Plexus)<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><a href=\"#lymph-vessels-and-nodes-of-the-colon\">Lymph Vessels and Nodes of The Colon<\/a><\/li>\n<li><a href=\"#nerves-of-the-colon\">Nerves of the Colon<\/a><\/li>\n<\/ol>\n<\/div><\/div>\n<\/div><\/div><\/div><\/div>\n\n<h2 id=\"introduction\">1. Introduction<\/h2>\n<p>The large intestine is the last part of the digestive system. Anatomically and functionally, the large intestine is divided into the colon, rectum, and <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a>.<\/p>\n<p>The colon is a thicker tube than the small intestine, about 150 cm long, through which stool is formed and stored. The colon narrows distally. It is about 7.5 cm wide in the cecum and only 2.5 cm wide at the end of the sigmoid colon.<\/p>\n<p>The liquid small intestine contents are poured into the colon, which absorbs the water and salt of this content and forms solid or semi-solid stool. Colon and rectal cancers are in 3rd place in men and 2nd place in women worldwide.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"parts-of-the-large-intestine\">2. Parts of the Large Intestine<\/h2>\n<figure id=\"attachment_15309\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/parts-of-colon.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15309\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/parts-of-colon-720x540.jpeg\" alt=\"Parts of colon\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/parts-of-colon-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/parts-of-colon-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/parts-of-colon.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Parts of colon<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<ul>\n<li><strong>Colon<\/strong>\n<ul>\n<li>Cecum and Appendix<\/li>\n<li>Ascending colon\n<ul>\n<li>Hepatic Flexure<\/li>\n<\/ul>\n<\/li>\n<li>Transverse colon\n<ul>\n<li>Splenic Flexure<\/li>\n<\/ul>\n<\/li>\n<li>Descending Colon<\/li>\n<li>Sigmoid Colon<\/li>\n<\/ul>\n<\/li>\n<li><strong>Rectum<\/strong><\/li>\n<li><strong><a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">Anal Canal<\/a><\/strong><\/li>\n<\/ul>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"difference-between-small-and-large-intestine\">3. Difference Between Small and Large Intestine<\/h2>\n<figure id=\"attachment_15307\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/difference-between-small-and-large-intestine.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15307\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/difference-between-small-and-large-intestine-720x540.jpeg\" alt=\"Difference between small and large intestine\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/difference-between-small-and-large-intestine-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/difference-between-small-and-large-intestine-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/difference-between-small-and-large-intestine.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Difference between small and large intestine<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<figure id=\"attachment_15339\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/taenia-coli.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15339\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/taenia-coli-720x540.jpeg\" alt=\"Taenia coli\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/taenia-coli-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/taenia-coli-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/taenia-coli.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Taenia coli<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<ul>\n<li><strong>Diameter:<\/strong> The diameter of the colon (about 3 inches, 7.5 cm) is larger than the small intestine (about 1 inch, 2.5 cm).<\/li>\n<li><strong>Length:<\/strong> The small intestine is longer (about 10-16 feet, 3-5 meters) than the large intestine (about 5 feet, 1.5 meters).<\/li>\n<li><strong>Appendix Epiploica:<\/strong> In the colon (except the rectum) there are fatty deposits covered with peritoneum. They are located on taenia libera and taenia omentalis.<\/li>\n<li><strong>Taeniae Coli (pl.) (Taenia Coli (sing.):<\/strong> The longitudinal (external) muscle layer of the colon is arranged in 3 separate bands (with 120 degrees intervals). The taeniae begin at the beginning of the colon (at the base of the cecum, at the root of the appendix), disperse in the rectum, and surround the rectum and anus. The names of these three taeniae are;\n<ul>\n<li>Free taenia (taenia libera)<\/li>\n<li>Mesocolic taenia (tenia mesocolica)<\/li>\n<li>Epiploic taenia (taenia omentalis)<\/li>\n<\/ul>\n<\/li>\n<li><strong>Haustura Coli:<\/strong> Sacculation in the colon (except the rectum), which give the colon its segmented appearance.<\/li>\n<li><strong>Mucosal Villi:<\/strong> Mucosal villi (small, finger-like projections) found in the small intestine are not found in the colon.<\/li>\n<li><strong>Function:<\/strong> Small intestine principally absorbs digested nutrients whereas the large intestine absorbs water and electrolytes.<\/li>\n<\/ul>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"peritoneal-relations-of-colon-and-taeniae-coli\">4. Peritoneal relations of colon and taeniae coli<\/h2>\n<figure id=\"attachment_15335\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/peritoneal-relations-of-colon-and-taeniae-coli.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15335\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/peritoneal-relations-of-colon-and-taeniae-coli-720x540.jpeg\" alt=\"Peritoneal relations of colon and taeniae coli\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/peritoneal-relations-of-colon-and-taeniae-coli-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/peritoneal-relations-of-colon-and-taeniae-coli-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/peritoneal-relations-of-colon-and-taeniae-coli.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Peritoneal relations of colon and taeniae coli<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"cecum\">5. Cecum<\/h2>\n<p>The cecum is the first and widest portion of the colon. It is in the right lower quadrant of the abdomen (right iliac fossa), with the appendix at its base. The cecum is relatively mobile. The ileum opens into the cecum on the medial wall of the cecum. As the largest section of the large intestine, the cecum is the most resistant to obstruction and the most susceptible to perforation. The three taeniae unite at the base of the cecum, and the appendix originates from here.<\/p>\n<h3 id=\"ileocecal-valve-ileocecal-valve\">Ileocecal Valve (Ileocecal Valve)<\/h3>\n<p>The ileocecal valve is a unidirectional sphincter between the ileum and the cecum, preventing the reflux of large intestine contents (stool) into the ileum; it is also known as the Bauhin valve or Tulp valve. The ileocecal valve relaxes as the small intestine expands, allowing the ileum's contents to pass into the cecum (colon). When the colon is distended, the tone of the ileocecal valve increases further. Thus, the contents of the colon cannot return to the small intestine.<\/p>\n<p>The ileocecal valve has an anti-diarrheal effect. In massive small bowel resection, preserving the ileocecal valve reduces short bowel syndrome and malabsorption.<\/p>\n<p>The ileocecal valve is competent in 75 percent of individuals. If the ileocecal valve is competent, the risk of closed-loop obstruction and perforation increases. In this case, there is usually no air in the small intestine on X-rays.<\/p>\n<p>Visualization of the ileocecal valve and appendix orifice indicates that the cecum has been reached on colonoscopy (i.e., all colon segments have been reached).<\/p>\n<p>Caecus means blind in Latin. Other names of the ileocecal valve are the Bauhin valve, Tulp or Tulpius valve, Varolius valve, ileal valve, colic valve, and ileocolic valve.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"appendix-appendix-vermiformis\">6. Appendix (Appendix Vermiformis)<\/h2>\n<p>The appendix is a worm-shaped (vermiform) extension of the cecum (a thin, blind tube). Its length is about 5&ndash;10 cm (maybe 1&ndash;25 cm). A healthy appendix's diameter does not exceed 6 mm.<\/p>\n<p>The origin of the appendix is relatively constant, where the three taeniae fuse at the base of the cecum (posterior to McBurney's point). However, other parts of the appendix are mobile, so it can be found in different positions: retrocecal (most), pelvic, subcecal, preileal, and postileal. The appendix can be reached during an appendectomy by following the tenia <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a> to the cecum (taenia libera).<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"ascending-colon\">7. Ascending Colon<\/h2>\n<p>The ascending colon is the segment of the colon after the cecum, approximately 12.5&ndash;20 cm long, that ascends upward (to the liver), makes a sharp turn to the left under the right lobe of the liver (hepatic flexure), and goes to the spleen (transverse colon). The ascending colon, like the descending colon, is considered retroperitoneal because the peritoneum only covers the medial, lateral, and <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a> parts of the ascending colon.<\/p>\n<p><strong>The hepatic flexure (right colic flexure)<\/strong> is located lateral to the gallbladder, <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a> to the lower pole of the right kidney, and the second (descending) part of the duodenum.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"transverse-colon\">8. Transverse Colon<\/h2>\n<p>The transverse colon has a downward convexity that starts from the hepatic flexure and extends to the splenic flexure. It is 40&ndash;50 cm long. The transverse colon is completely intraperitoneal, and the most mobile part of the colon has a mesentery (transverse mesocolon).<\/p>\n<p>The transverse mesocolon divides the abdominal cavity into two compartments, the supramesocolic and inframesocolic spaces (compartments). Thus, the transverse mesocolon serves as a natural barrier against the spread of peritonitis and abscess.<\/p>\n<p>The gastrocolic omentum (ligament) connects the anterosuperior portion of the transverse colon to the stomach's greater curvature. During colonoscopy, the gastrocolic ligament creates a triangular appearance inside the transverse colon.<\/p>\n<p>When the gastrocolic ligament is opened, the bursa omentalis (lesser sac) is entered. In other words, the posterior surface of the stomach and the pancreas are exposed. For instance, the gastrocolic ligament is opened to inspect the stomach's posterior surface in cases of gastric injuries or to perform a distal pancreatectomy.<\/p>\n<p><strong>The Splenic Flexure (Left Colic Flexure):<\/strong> The transverse colon is attached to the lower part of the spleen (splenocolic ligament) and the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;The &amp;lt;strong&amp;gt;diaphragm&amp;lt;\/strong&amp;gt; is a large, dome-shaped musculomembranous (musculotendinous) structure that separates the abdominal and thoracic (chest) cavities....&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/diaphragm\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/diaphragm\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">diaphragm<\/a> (phrenicocolic ligament) on the left side. It then makes a sharp downward turn. The splenic flexure is higher and deeper than the hepatic flexure. The splenic flexure is the most fixed part of the large intestine after the rectum.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"descending-colon\">9. Descending Colon<\/h2>\n<p>The descending colon starts from the splenic flexure and descends to the sigmoid colon at the level of the greater pelvis entrance. It is about 25&ndash;30 cm in length. It descends anteriorly to the kidney and slightly medially. As the peritoneum covers only the lateral, <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a>, and medial surfaces of the descending colon, it is retroperitoneal (like the ascending colon). The descending colon is deeper and thinner than the ascending colon.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"sigmoid-colon\">10. Sigmoid Colon<\/h2>\n<p>The sigmoid colon is the narrowest and most mobile segment of the large intestine, which is between the descending colon and the rectum. Because of its narrow diameter, the sigmoid colon is the most vulnerable segment of the large intestine to obstruction.<\/p>\n<p>The sigmoid colon begins at the entrance to the greater pelvis and terminates at the level of the 3rd sacral vertebra (rectosigmoid junction; sacral promontory for some sources).<\/p>\n<p>The sigmoid colon consists of two parts, the iliac (fixed) and pelvic (mobile, mesenteric). The sigmoid colon is about 40 cm long. The middle part of the sigmoid colon may extend into the right lower quadrant.<\/p>\n<p>Etymology: Sigma is the eighteenth letter of the Greek alphabet (uppercase: &Sigma;, lowercase: &sigma;, en of word: &sigmaf;). The sigmoid colon is similar to the lowercase sigma at the end of the word (&sigmaf;).<\/p>\n<h3 id=\"sigmoid-colon-mesentery\">Sigmoid Colon Mesentery<\/h3>\n<p>The mobile (pelvic) part of the sigmoid colon has an omega-shaped (&Omega;) mesentery (long but narrow-based). Therefore, the most common site of volvulus is the sigmoid colon (2nd cecum).<\/p>\n<p>The sigmoid mesocolon adhesion line to the posterior abdominal wall is in an inverted &ldquo;V&rdquo; shape. The <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Apex (medicine)&amp;lt;\/h1&amp;gt;\nApex refers to the highest or most pointy end of a cone or pyramid-shaped structure. While the term &amp;quot;tip&amp;quot; is generally used for...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/apex\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/apex\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">apex<\/a> is around the bifurcation of the left common iliac artery. The left leg is medial to the left psoas muscle. The right leg descends into the pelvis and ends in front of the third sacral segment in the midline.<\/p>\n<p>Intersigmoid Fossa (Recess): When the sigmoid colon is tilted medially, the depression in the middle of the line where the meson attaches to the posterior abdominal wall is called the intersigmoid fossa. It is more pronounced in fetal life. The left ureter descends behind this fossa. The intersigmoid fossa can be used as a landmark to locate the left ureter and avoid injury.<\/p>\n<h3 id=\"rectosigmoid-junction\">Rectosigmoid Junction<\/h3>\n<p>The rectosigmoid junction can be identified by six characteristics (more precisely, where the sigmoid colon ends and the rectum begins).<\/p>\n<ol>\n<li>The disappearance of colon haustra (rectum is straight)<\/li>\n<li>Narrowing of the intestinal lumen<\/li>\n<li>The disappearance of the sigmoid mesocolon<\/li>\n<li>Dispersion of taeniae and covering the rectum in a single sheath.<\/li>\n<li>The disappearance of epiploic appendices<\/li>\n<li>Mucosal difference: The rectal mucosa is smooth and flat, and there are 3 valves (Houston valves). There are prominent mucosal folds in the sigmoid colon mucosa.<\/li>\n<\/ol>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"rectum\">11. Rectum<\/h2>\n<figure id=\"attachment_15331\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/rectum-and-anal-canal-anatomy.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15331\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/rectum-and-anal-canal-anatomy-720x540.jpeg\" alt=\"Rectum and anal canal anatomy\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/rectum-and-anal-canal-anatomy-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/rectum-and-anal-canal-anatomy-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/rectum-and-anal-canal-anatomy.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Rectum and anal canal anatomy<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<p>The rectum begins after the sigmoid colon (at the level of SIII, according to some sources, the sacral promontory) and terminates at the anus. The <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anorectal&amp;lt;\/h1&amp;gt;\n&amp;lt;figure id=&amp;quot;attachment_15331&amp;quot; class=&amp;quot;thumbnail wp-caption alignnone&amp;quot; style=&amp;quot;width: 1024px&amp;quot;&amp;gt;&amp;lt;figcaption class=&amp;quot;caption wp-caption-text&amp;quot;&amp;gt;Rectum and anal canal anatomy&amp;lt;\/figcaption&amp;gt;&amp;lt;\/figure&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;Anorectal refers to the lowest parts of the large intestine, including the anus and rectum.&amp;lt;br \/&amp;gt;For example,...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anorectal<\/a> junction refers to the point where the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> meets the rectum. This junction is anatomically defined externally by the puborectal and pelvic floor muscles and internally by the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">dentate line<\/a>.<\/p>\n<p>The word &quot;rectum&quot; comes from Latin (rectus), meaning straight. There are three mucosal folds in the rectum (upper left, middle right, and lower left), called the valves of Houston. The rectum is 12 cm long. The middle part of the rectum is wider (ampulla recti).<\/p>\n<p>The Function of the Rectum: Stool coming from the sigmoid colon is stored in the rectum before defecation. When the rectum is distended, the internal and external anal sphincters relax (rectoanal inhibitory reflex), the rectum contracts and shortens, and defecation occurs. If a person voluntarily holds back his or her stool (external sphincter), the stool returns to the sigmoid colon, and the water in the stool continues to be absorbed, causing the stool to harden even more.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"anal-canal\">12. Anal Canal<\/h2>\n<figure id=\"attachment_15325\" class=\"thumbnail wp-caption alignnone\" style=\"width: 1024px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/anal-canal-anatomy.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-15325\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/anal-canal-anatomy.jpeg\" alt=\"Anal canal anatomy\" width=\"1024\" height=\"768\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/anal-canal-anatomy.jpeg 1024w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/anal-canal-anatomy-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/anal-canal-anatomy-768x576.jpeg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Anal canal anatomy<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<p>The <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> is the last part of the large intestine, with a length of 4-5 cm. It is between the rectum and the anal verge (anal orifice, anus).<\/p>\n<p>The keratinized, pigmented perianal skin around the anal verge has skin appendages (hair, sweat, and sebaceous glands). The <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> skin (<a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anoderm&amp;lt;\/h1&amp;gt;\n&amp;lt;figure id=&amp;quot;attachment_15325&amp;quot; class=&amp;quot;thumbnail wp-caption alignnone&amp;quot; style=&amp;quot;width: 1024px&amp;quot;&amp;gt;&amp;lt;figcaption class=&amp;quot;caption wp-caption-text&amp;quot;&amp;gt;Anal canal anatomy&amp;lt;\/figcaption&amp;gt;&amp;lt;\/figure&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;\nThe anoderm is the epithelial layer lining the anal canal between the anal verge and the pectinate line (dentate...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anoderm\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anoderm\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anoderm<\/a>) above the anal verge is also pigmented and keratinized and is pain-sensitive like the skin, but without skin appendages.<\/p>\n<h3 id=\"surgical-anal-canal\">Surgical Anal Canal<\/h3>\n<p>The upper border between the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> and the rectum is accepted as the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anorectal&amp;lt;\/h1&amp;gt;\n&amp;lt;figure id=&amp;quot;attachment_15331&amp;quot; class=&amp;quot;thumbnail wp-caption alignnone&amp;quot; style=&amp;quot;width: 1024px&amp;quot;&amp;gt;&amp;lt;figcaption class=&amp;quot;caption wp-caption-text&amp;quot;&amp;gt;Rectum and anal canal anatomy&amp;lt;\/figcaption&amp;gt;&amp;lt;\/figure&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;Anorectal refers to the lowest parts of the large intestine, including the anus and rectum.&amp;lt;br \/&amp;gt;For example,...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anorectal<\/a> ring (<a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anorectal&amp;lt;\/h1&amp;gt;\n&amp;lt;figure id=&amp;quot;attachment_15331&amp;quot; class=&amp;quot;thumbnail wp-caption alignnone&amp;quot; style=&amp;quot;width: 1024px&amp;quot;&amp;gt;&amp;lt;figcaption class=&amp;quot;caption wp-caption-text&amp;quot;&amp;gt;Rectum and anal canal anatomy&amp;lt;\/figcaption&amp;gt;&amp;lt;\/figure&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;Anorectal refers to the lowest parts of the large intestine, including the anus and rectum.&amp;lt;br \/&amp;gt;For example,...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anorectal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anorectal<\/a> angle). Its average length is 4-5 cm. &#8532; of the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> is above the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">dentate line<\/a>, and &#8531; is below the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">dentate line<\/a>.<\/p>\n<h3 id=\"anatomical-anal-canal\">Anatomical Anal Canal<\/h3>\n<p>The upper border of the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a> is considered the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">dentate line<\/a> (<a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">pectinate line<\/a>). Its average length is 2.5-3 cm.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"ligaments-of-the-colon\">13. Ligaments of the Colon<\/h2>\n<p>Gastrocolic Ligament: The part of the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;The Greater Omentum&amp;lt;\/h1&amp;gt;\n&amp;lt;strong&amp;gt;The greater omentum&amp;lt;\/strong&amp;gt;, also known as the &amp;lt;strong&amp;gt;omentum majus&amp;lt;\/strong&amp;gt; or &amp;lt;strong&amp;gt;epiploon&amp;lt;\/strong&amp;gt;, is a four-layered peritoneal membrane that extends from the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/greater-omentum\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/greater-omentum\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">greater omentum<\/a> between the greater curvature of the stomach and the transverse colon is called the gastrocolic ligament. By opening the gastrocolic ligament, it is accessed the posterior wall of the stomach, and the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a> surface of the pancreas, namely the lesser sac.<br>\nSplenocolic Ligament: The firm peritoneal connection between the lower pole of the spleen and the splenic flexure.<br>\nPhrenicocolic Ligament: The connection between the splenic flexure and the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;The &amp;lt;strong&amp;gt;diaphragm&amp;lt;\/strong&amp;gt; is a large, dome-shaped musculomembranous (musculotendinous) structure that separates the abdominal and thoracic (chest) cavities....&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/diaphragm\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/diaphragm\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">diaphragm<\/a><\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"arteries-of-the-colon\">14. Arteries of the Colon<\/h2>\n<figure id=\"attachment_15315\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-arteries.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15315\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-arteries-720x540.jpeg\" alt=\"Colon arteries\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-arteries-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-arteries-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-arteries.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Colon arteries<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<p>The arteries of the colon include the last three branches of the superior mesenteric artery and all branches of the inferior mesenteric artery.<\/p>\n<ul>\n<li><strong>Branches of Superior Mesenteric Artery:<\/strong> All branches of superior mesenteric artery are listed below for easier understanding, the last three branches are related to the colon.\n<ul>\n<li>Inferior Pancreaticoduodenal Artery<\/li>\n<li>Jejunal and Ileal branches<\/li>\n<li>Middle Colic Artery supplies the transverse colon<\/li>\n<li>Right Colic Artery supplies the ascending colon<\/li>\n<li>Ileocolic Artery supplies the terminal ileum, appendix, cecum, and proximal ascending colon.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Branches of the Inferior Mesenteric Artery:<\/strong> All branches supply the left colon. Respectively;\n<ul>\n<li>Left Colic Artery supplies the descending colon<\/li>\n<li>Sigmoidal Branches supply the sigmoid colon<\/li>\n<li>Superior Rectal Artery supplies the proximal rectum<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3 id=\"ileocolic-artery\">Ileocolic Artery<\/h3>\n<p>It is the last branch of the superior mesenteric artery. The ileocolic artery also divides into two branches.<\/p>\n<ul>\n<li>The superior branch ascends, anastomose with the descending branch of the right colic artery.<\/li>\n<li>The inferior branch gives cecal branches, appendicular artery, and ileal branches.<\/li>\n<\/ul>\n<h3 id=\"right-colic-artery\">Right Colic Artery<\/h3>\n<p>The right colic artery supplies the ascending colon. As it approaches the colon, it divides into two branches.<\/p>\n<ul>\n<li>The descending branch anastomoses with the ascending branch of the ileocolic artery.<\/li>\n<li>The ascending branch anastomoses with the right branch of the middle colic artery.<\/li>\n<\/ul>\n<h3 id=\"middle-colic-artery\">Middle Colic Artery<\/h3>\n<p>The middle colic artery runs inside the transverse mesocolon and divides into two branches as it approaches the colon.<\/p>\n<ul>\n<li>The right branch of the middle colic artery anastomoses with the ascending branch of the right colic artery<\/li>\n<li>The left branch of the middle colic artery anastomoses with the ascending branch of the left colic artery (Arc of Riolan).<\/li>\n<\/ul>\n<p><strong>The Arc of Riolan<\/strong>, also called the Riolan anastomosis, is part of the <strong>marginal artery of Drummond<\/strong>. The arc of Riolan, also known as the meandering mesenteric artery or the central mesenteric artery, is an important arterial connection between the superior mesenteric artery (SMA) and the inferior mesenteric artery (IMA). This connection is significant because it allows for collateral blood flow between the two arteries, which supply blood to the small and large intestines.<\/p>\n<p>In cases of arterial occlusion or stenosis in one of these arteries, the arc of Riolan can provide an alternative route for blood flow to the affected area of the intestine, preventing ischemia (insufficient blood supply) and potential tissue damage.<\/p>\n<h3 id=\"left-colic-artery\">Left Colic Artery<\/h3>\n<p>The left colic artery is the first branch of the inferior mesenteric artery. The left colic artery divides into two branches in the retroperitoneum.<\/p>\n<ul>\n<li>The ascending branch supplies the proximal descending colon and the distal transverse colon. The ascending branch anastomoses with the left branch of the middle colic artery to form the Riolan arch.<\/li>\n<li>The descending branch supplies the distal descending colon, and anastomosis with the first sigmoid artery branch.<\/li>\n<\/ul>\n<h3 id=\"sigmoidal-arteries\">Sigmoidal Arteries<\/h3>\n<p>The sigmoid artery typically consists of 2&ndash;4 branches that run in the sigmoid mesocolon. The uppermost (superior) sigmoid artery anastomoses with the descending branch of the left colic artery. The sigmoidal arteries supply the distal descending colon and the sigmoid colon.<\/p>\n<h3 id=\"rectal-arteries\">Rectal Arteries<\/h3>\n<h4 id=\"superior-rectal-hemorrhoidal-artery\">Superior Rectal (Hemorrhoidal) Artery<\/h4>\n<p>The superior rectal artery is the terminal branch of the inferior mesenteric artery. The superior rectal artery enters the pelvis on its medial side and passes through the sigmoid colon mesentery. It divides into two branches at the level of the S3 vertebra, giving small branches to the right and left of the rectum, and descends to the level of the internal anal sphincter. The superior rectal artery supplies the proximal part of the rectum.<\/p>\n<h4 id=\"middle-rectal-hemorrhoidal-artery\">Middle Rectal (Hemorrhoidal) Artery<\/h4>\n<p>The middle rectal artery is a branch of the internal iliac artery that supplies the distal rectum.<\/p>\n<h4 id=\"inferior-rectal-hemorrhoidal-artery\">Inferior Rectal (Hemorrhoidal) Artery<\/h4>\n<p>The inferior rectal artery is a branch of the internal pudendal artery, which, in turn, is a branch of the internal iliac artery. The inferior rectal artery supplies the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a>, anal muscles, anal area, and surrounding gluteal skin. The internal pudendal artery supplies blood to the perineum, which is the region between the anus and the external genitalia. Specifically, it provides blood supply to the external genitalia, including the clitoris, labia majora, and scrotum, as well as the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a>, perianal skin, and the muscles and structures in the pelvic floor.<\/p>\n<p>There is a well-developed network between the terminal branches of the superior, middle, and inferior rectal arteries. This network makes the rectum resistant to ischemia.<\/p>\n<h3 id=\"marginal-artery-of-drummond\">Marginal Artery of Drummond<\/h3>\n<p>The arteries of the colon anastomose with each other at the colon's margin before entering the colon, forming Drummond's marginal artery. At the edge of the splenic flexure, the marginal artery of Drummond is called the arc of Riolan. Therefore, the arc of Riolan is an important arterial connection between the superior mesenteric artery (SMA) and the inferior mesenteric artery (IMA).<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"veins-of-the-colon\">15. Veins of the Colon<\/h2>\n<figure id=\"attachment_15317\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-veins.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15317\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-veins-720x540.jpeg\" alt=\"Colon veins\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-veins-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-veins-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-veins.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Colon veins<\/figcaption><\/figure>\n<p>Except for the lower part of the rectum, the venous <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Drainage (Medicine)&amp;lt;\/h1&amp;gt;\nDrainage refers to the removal or emptying of fluid. This can be better explained with examples.\n&amp;lt;h2&amp;gt;Abscess Drainage&amp;lt;\/h2&amp;gt;\nDraining...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">drainage<\/a> of the stomach, small and large intestines, spleen, pancreas, and gallbladder is to the liver via the portal vein.<\/p>\n<p>The blood from the portal vein flows into the liver through specialized blood vessels called hepatic sinusoids. The hepatic sinusoids are a network of capillaries that are lined by specialized cells called hepatic stellate cells and Kupffer cells. These cells help filter and process the blood that flows through the sinusoids. After passing through the hepatic sinusoids, the blood from the portal vein is collected by the hepatic veins, which drain into the inferior vena cava.<\/p>\n<p>The venous <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Drainage (Medicine)&amp;lt;\/h1&amp;gt;\nDrainage refers to the removal or emptying of fluid. This can be better explained with examples.\n&amp;lt;h2&amp;gt;Abscess Drainage&amp;lt;\/h2&amp;gt;\nDraining...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">drainage<\/a> of the colon occurs via both the superior and inferior mesenteric veins.<br>\nThe superior mesenteric vein drains blood from the small intestine, ascending colon, and transverse colon, while the inferior mesenteric vein drains blood from the descending colon, sigmoid colon, and rectum.<\/p>\n<h3 id=\"superior-mesenteric-vein\">Superior Mesenteric Vein<\/h3>\n<p>The superior mesenteric vein is like a venous replica of the superior mesenteric artery. The superior mesenteric vein drains the jejunal, ileal, ileocolic, right, and middle colic veins. In other words, the blood from the jejunum, ileum, cecum, ascending colon, and transverse colon drains into the superior mesenteric vein.<\/p>\n<p>The superior mesenteric vein arises from the right iliac fossa and ascends, passing in front of the horizontal part of the duodenum and then behind the pancreatic neck. At the level of the upper edge of the pancreas, the splenic vein joins the superior mesenteric vein, and together they form the portal vein (at the level of the L2 vertebra). The inferior mesenteric vein drains into the splenic vein. Sometimes the superior mesenteric vein, inferior mesenteric vein, and splenic vein unite at the same junction (trifurcation).<\/p>\n<h3 id=\"inferior-mesenteric-vein\">Inferior Mesenteric Vein<\/h3>\n<p>The inferior mesenteric vein drains blood from the rectum, sigmoid colon, and descending colon.<\/p>\n<p>The inferior mesenteric vein is like a venous replica of the inferior mesenteric artery. The inferior mesenteric vein begins in the rectum as the superior rectal vein; as it ascends, it receives the sigmoidal veins and the left colic vein. The inferior mesenteric vein drains into the splenic vein. The splenic vein joins with the superior mesenteric vein to form the portal vein.<\/p>\n<h4 id=\"superior-rectal-hemorrhoidal-vein\">Superior Rectal (Hemorrhoidal) Vein<\/h4>\n<p>The superior rectal vein drains the rectum (via the superior (internal) hemorrhoidal plexus). The inferior mesenteric vein is formed by the convergence of several veins, including the left colic vein, the sigmoid veins, and the superior rectal vein.<\/p>\n<h4 id=\"middle-rectal-hemorrhoidal-vein\">Middle Rectal (Hemorrhoidal) Vein<\/h4>\n<p>The middle rectal vein, along with the inferior rectal vein, drains blood from the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a>, anal muscles, anal region, and surrounding gluteal skin (via the inferior (external) hemorrhoidal plexus). It joins the internal iliac vein.<\/p>\n<h4 id=\"inferior-rectal-hemorrhoidal-vein\">Inferior Rectal (Hemorrhoidal) Vein<\/h4>\n<p>The inferior rectal vein, along with the middle rectal vein, drains blood from the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;&amp;lt;\/h1&amp;gt;\nAnal canal anatomy&amp;lt;div class=&amp;quot;hrule clearfix&amp;quot; style=&amp;quot; height:1px&amp;quot;&amp;gt;&amp;lt;\/div&amp;gt;&amp;lt;br \/&amp;gt;The anal canal is the final 4-5 cm of the colon, surrounded by muscles at the end of the digestive system, between the rectum...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anal-canal\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anal canal<\/a>, anal muscles, anal region, and surrounding gluteal skin (via the inferior (external) hemorrhoidal plexus). The inferior rectal vein, which begins as several branches, joins to form the internal pudendal vein. After receiving the middle rectal vein and other small veins, the internal pudendal vein becomes the internal iliac vein.<\/p>\n<h4 id=\"rectal-venous-plexus-hemorrhoidal-plexus\">Rectal Venous Plexus (Hemorrhoidal Plexus)<\/h4>\n<p>The veins draining the distal rectum and the anus arise from two venous plexuses.<\/p>\n<ul>\n<li><strong>Internal (superior) hemorrhoidal (rectal) plexus<\/strong><\/li>\n<li><strong>External (inferior) hemorrhoidal (rectal) plexus<\/strong><\/li>\n<\/ul>\n<p>The communications between the superior and inferior hemorrhoidal plexuses are dilated in portal hypertension, acting as portosystemic collaterals.<\/p>\n<p>The internal hemorrhoidal plexus is located submucosal and just above the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anorectal line<\/a>. It drains into the superior hemorrhoidal (rectal) vein &gt; inferior mesenteric vein &gt; portal system.<\/p>\n<p>Dilatation and elongation of the internal hemorrhoidal veins cause internal hemorrhoidal disease. Because the caval vessels lack venous valves, portal hypertension is exactly reflected in the internal hemorrhoid plexus. Therefore, there is a tendency to develop internal hemorrhoidal disease.<\/p>\n<p><strong>The external hemorrhoidal plexus<\/strong>, located outside the muscular layer and below the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Pectinate Line&amp;lt;\/h1&amp;gt;\nThe &amp;lt;strong&amp;gt;pectinate line&amp;lt;\/strong&amp;gt;, also known as the dentate line, anorectal line, or anocutaneous line, is a serrated line that separates the...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/pectinate-line\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anorectal line<\/a>, drains into two veins:<\/p>\n<p>Inferior hemorrhoidal (rectal) vein &gt; internal pudendal vein &gt; internal iliac vein &gt; caval system<br>\nMiddle hemorrhoidal (rectal) vein &gt; internal iliac vein &gt; caval system<\/p>\n<p>Enlargement of the external hemorrhoidal plexus causes external hemorrhoidal disease.<\/p>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"lymph-vessels-and-nodes-of-the-colon\">16. Lymph Vessels and Nodes of The Colon<\/h2>\n<figure id=\"attachment_15333\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-lymph-nodes-and-lymph-vessels.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15333\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-lymph-nodes-and-lymph-vessels-720x540.jpeg\" alt=\"Colon lymph nodes and lymph vessels\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-lymph-nodes-and-lymph-vessels-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-lymph-nodes-and-lymph-vessels-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/colon-lymph-nodes-and-lymph-vessels.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Colon lymph nodes and lymph vessels<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<figure id=\"attachment_15329\" class=\"thumbnail wp-caption alignnone\" style=\"width: 720px\"><a href=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/regional-lymph-node-groups-of-the-colon.jpeg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-15329\" src=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/regional-lymph-node-groups-of-the-colon-720x540.jpeg\" alt=\"Regional lymph node groups of the colon\" width=\"720\" height=\"540\" srcset=\"https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/regional-lymph-node-groups-of-the-colon-720x540.jpeg 720w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/regional-lymph-node-groups-of-the-colon-768x576.jpeg 768w, https:\/\/www.turkcerrahi.com\/wp-content\/uploads\/regional-lymph-node-groups-of-the-colon.jpeg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\"\/><\/a><figcaption class=\"caption wp-caption-text\">Regional lymph node groups of the colon<\/figcaption><\/figure>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<p>The lymphatic flow of the gastrointestinal tract in the abdomen begins in the tissue and ends in large bundles of lymph nodes at the root of the <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Anterior&amp;lt;\/h1&amp;gt;\nAnterior refers to &amp;quot;front&rdquo;, &amp;quot;in front of&rdquo;, or &amp;quot;close to the front&rdquo;. In human anatomy, it refers to the front surface of the body or...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/anterior\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">anterior<\/a> branches of the abdominal aorta (preaortic lymph nodes).<\/p>\n<p><strong>Preaortic lymph nodes are divided into three groups:<\/strong><\/p>\n<ol>\n<li>Celiac lymph nodes<\/li>\n<li>Superior mesenteric lymph nodes and<\/li>\n<li>Inferior mesenteric lymph nodes<\/li>\n<\/ol>\n<p>Inferior mesenteric lymph nodes &gt; drain into superior mesenteric lymph nodes &gt; these drain into celiac lymph nodes, which in turn drain into cisterna chyli &gt; which drain into left subclavian vein<\/p>\n<p>The lymphatic <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemBody&gt;&amp;lt;h1&amp;gt;Drainage (Medicine)&amp;lt;\/h1&amp;gt;\nDrainage refers to the removal or emptying of fluid. This can be better explained with examples.\n&amp;lt;h2&amp;gt;Abscess Drainage&amp;lt;\/h2&amp;gt;\nDraining...&lt;\/div&gt;&lt;div class=glossaryTooltipMoreLinkWrapper&gt;&lt;a class=glossaryTooltipMoreLink href=https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/ &gt;Read more&lt;\/a&gt;&lt;\/div&gt;\" href=\"https:\/\/www.turkcerrahi.com\/en\/medical-dictionary\/drainage\/\" data-mobile-support=\"0\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">drainage<\/a> of the colon and the lymph node groups are arranged as follows, respectively:<\/p>\n<ul>\n<li><strong>Submucosal and Subserosal Lymphatic Plexus<\/strong> (interconnected)<\/li>\n<li><strong>Epicolic Lymph Nodes<\/strong> (Located in the colon wall, below the serosa, and in the epiploic appendices. Most numerous in the sigmoid colon)<\/li>\n<li><strong>Paracolic Lymph Nodes<\/strong> (Lymph nodes around their corresponding arterial arcades)<\/li>\n<li><strong>Intermediate Lymph Nodes<\/strong> (Through segmental colonic vessels, i.e., lymph nodes around ileocolic, right colic, middle colic, left colic, and sigmoidal arteries)<\/li>\n<li><strong>Main (Principal) Lymph Nodes<\/strong>\n<ul>\n<li>Lymph nodes around the Superior Mesenteric Artery Root<\/li>\n<li>Lymph Nodes around the Inferior Mesenteric Artery Root<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<h2 id=\"nerves-of-the-colon\">17. Nerves of the Colon<\/h2>\n<p>The large intestine is controlled by two nervous systems (intrinsic, and extrinsic)<\/p>\n<ul>\n<li><strong>Enteric Nervous System (Intrinsic)<\/strong><\/li>\n<li><strong>Autonomic Nervous System (Extrinsic)<\/strong>\n<ul>\n<li><em>Sympathetic Nervous System (Thoracolumbar Division)<\/em>\n<ul>\n<li>T11-12 &gt; Sympathetic chain ganglion &gt; Superior mesenteric artery ganglion &gt; Right colon<\/li>\n<li>L1-2 &gt; sympathetic chain ganglion &gt; inferior mesenteric artery ganglion &gt; Left colon<\/li>\n<li>Lumbar splanchnic nerves, superior and inferior hypogastric plexuses &gt; Rectum<\/li>\n<\/ul>\n<\/li>\n<li><em>Parasympathetic Nervous System (Craniosacral Division)<\/em>\n<ul>\n<li>Vagus nerve (X. Cranial Nerve) &gt; Right Colon (cecum, ascending colon, transverse colon)<\/li>\n<li>Sacral 2-4 nerves &gt; pelvic splanchnic nerves (n. erigentes) &gt; Left Colon (descending colon, sigmoid, rectum)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>The sympathetic innervation (nerves) of the colon inhibits (reduces) colonic peristalsis and secretions and causes contraction of the ileocolic and rectal sphincters.<\/p>\n<p>The parasympathetic innervation (nerves) of the colon stimulates (increases) colonic peristalsis and secretions while relaxing the ileocolic and rectal sphincters.<\/p>\n<p>Visceral sensory fibers (visceral afferent fibers), including those in the colon, are carried by both sympathetic and parasympathetic nerves.<\/p>\n<ul>\n<li>Visceral sensory fibers accompanying the sympathetic fibers (carried within the sympathetic nerves) transmit pain.<\/li>\n<li>Visceral sensory fibers accompanying the parasympathetic fibers (carried within the parasympathetic nerves) carry the impulses formed in the chemoreceptors and baroreceptors, they carry information about reflex activity and physiological processes.<\/li>\n<\/ul>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<div class=\"row\"> <div class=\"col-md-6  \">\n<p style=\"text-align: center;\">&lt; <a href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/\" title=\"Colon, Rectum, and Anus\">Colon, Rectum, and Anus<\/a>\n<\/p><\/div><div class=\"col-md-6  \">\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/rectum-and-anal-canal-anatomy\/\" title=\"Anatomy of the Rectum and Anal Canal\">Anatomy of the Rectum and Anal Canal<\/a> &gt;<\/p>\n<\/div><\/div>\n<div class=\"hrule clearfix\" style=\" height:1px\"><\/div>\n<\/div><\/div><\/div><div id=\"pgc-16391-0-1\" class=\"panel-grid-cell\"><div id=\"panel-16391-0-1-0\" class=\"so-panel widget widget_nav_menu panel-first-child panel-last-child\" data-index=\"1\"><div class=\"panel-widget-style panel-widget-style-for-16391-0-1-0\"><h3 class=\"widget-title\">Colon, Rectum and Anus<\/h3><ul id=\"menu-colon-rectum-and-anus\" class=\"menu\"><li class=\" menu-item-16406 menu-item menu-colon-rectum-and-anus-overview\"><a href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/\"><span>Colon, Rectum, and Anus &ndash; Overview<\/span><\/a><\/li>\n<li class=\" menu-item-16407 menu-item menu-anatomy-of-the-colon\"><a href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/colon-anatomy\/\"><span>Anatomy of the Colon<\/span><\/a><\/li>\n<li class=\" menu-item-16408 menu-item menu-anatomy-of-the-rectum-and-anal-canal\"><a href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/rectum-and-anal-canal-anatomy\/\"><span>Anatomy of the Rectum and Anal Canal<\/span><\/a><\/li>\n<\/ul><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>1. Introduction The large intestine is the last part of the digestive system. Anatomically and functionally, the large intestine is divided into the colon, rectum, and anal canal. The colon is a thicker tube than the small intestine, about 150 &hellip; <a class=\"kt-excerpt-readmore\" href=\"https:\/\/www.turkcerrahi.com\/en\/general-surgery-articles\/colon-rectum-anus\/colon-anatomy\/\" aria-label=\"Anatomy of the Colon\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":16386,"menu_order":88,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-16391","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/pages\/16391","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/comments?post=16391"}],"version-history":[{"count":4,"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/pages\/16391\/revisions"}],"predecessor-version":[{"id":19045,"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/pages\/16391\/revisions\/19045"}],"up":[{"embeddable":true,"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/pages\/16386"}],"wp:attachment":[{"href":"https:\/\/www.turkcerrahi.com\/en\/wp-json\/wp\/v2\/media?parent=16391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}