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Transverse colon

Medically Reviewed by Anatomy Team

  • Last updated on January 24, 2025

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The transverse colon is the longest and most mobile segment of the large intestine, connecting the ascending colon to the descending colon.[7] It is responsible for the continued processing and transport of digestive material. Suspended by the transverse mesocolon, it is intraperitoneal and has a distinct horizontal orientation.

Where is Transverse colon Located?

The transverse colon is located in the upper abdomen. It extends from the hepatic flexure (right colic flexure) near the liver to the splenic flexure (left colic flexure) near the spleen. It crosses the abdomen anteriorly to the pancreas and stomach, running horizontally across the abdominal cavity.

Anatomy

The transverse colon is a key section of the large intestine and the most mobile segment of the colon.[5] It plays a central role in connecting the ascending and descending colons while occupying a prominent position in the abdominal cavity. Below is a detailed description of its anatomy:

Location and Orientation

  • The transverse colon is located in the upper abdomen, spanning horizontally across the abdominal cavity.
  • It begins at the hepatic flexure (right colic flexure), where it continues from the ascending colon, and ends at the splenic flexure (left colic flexure), where it transitions into the descending colon.
  • Its position may vary due to its mobility and the presence of the transverse mesocolon, often dipping below the umbilicus.[3]

Dimensions

The transverse colon is the longest segment of the colon, measuring approximately 45-50 cm in length, though this can vary.

Structure

The wall of the transverse colon is composed of the four typical layers found throughout the gastrointestinal tract:

Mucosa:

Submucosa:

  • Contains connective tissue, blood vessels, lymphatics, and nerves.
  • Provides support to the mucosal layer.

Muscularis Externa:

Consists of two layers of smooth muscle:

  • Inner circular layer: Facilitates segmentation.
  • Outer longitudinal layer: Arranged into three distinct bands called teniae coli, which run along the length of the colon.

The teniae coli cause the colon to have sacculations, or haustra, giving it a segmented appearance.

Serosa/Adventitia:

The transverse colon is covered by serosa, as it is an intraperitoneal organ, suspended by the transverse mesocolon.

Peritoneal Relationships

  • The transverse colon is an intraperitoneal organ, meaning it is entirely surrounded by peritoneum.
  • It is suspended from the posterior abdominal wall by the transverse mesocolon, a fold of peritoneum containing blood vessels, nerves, and lymphatics.[1]

Vascular Supply

Arterial Supply:

Venous Drainage:

Blood drains into the superior mesenteric vein (SMV), which contributes to the portal venous system.

Lymphatic Drainage

Lymphatic vessels from the transverse colon drain into:

  • Superior mesenteric lymph nodes (proximal portion).
  • Inferior mesenteric lymph nodes (distal portion).
  • These nodes eventually drain into the thoracic duct.

Nervous Supply

Sympathetic Innervation:

Provided by the superior mesenteric plexus.[8]

  • Parasympathetic Innervation: Supplied by the vagus nerve, which stimulates peristalsis and secretion.
  • These nerves regulate motility and secretion in the transverse colon.

Relationships to Adjacent Structures

  • Superiorly: Related to the liver (on the right), stomach, and spleen (on the left).
  • Posteriorly: Lies anterior to the pancreas and parts of the duodenum.
  • Inferiorly: Related to loops of the small intestine.
  • Anteriorly: Covered by the greater omentum, which drapes over it.

Function

The transverse colon plays a vital role in the digestion process, serving as an intermediary segment of the large intestine. Its functions revolve around the continued processing of digested material, reabsorption, and preparation of waste for elimination. Below is a detailed breakdown of its functions:

 Transport of Digestive Material

The transverse colon moves partially digested material (chyme) from the ascending colon to the descending colon:

  • Peristaltic Movements:The muscularis externa performs rhythmic contractions to propel material through the colon.
  • Mass Movements:Strong, coordinated contractions occur a few times daily, moving large quantities of material toward the rectum.

Water and Electrolyte Absorption

The transverse colon absorbs:

  • Water:The colon reabsorbs significant amounts of water from the chyme, converting it into more solid feces.
  • Electrolytes:Important electrolytes like sodium and chloride are absorbed, maintaining the body’s fluid and electrolyte balance.[6]

Fermentation of Undigested Material

  • The transverse colon hosts a diverse population of gut microbiota that ferment undigested carbohydrates:
  • This process produces short-chain fatty acids (SCFAs), such as butyrate, which:
  • Serve as an energy source for colonocytes.
  • Support the health of the colonic mucosa.
  • Fermentation also produces gases, such as carbon dioxide, hydrogen, and methane, which are eventually expelled as flatus.

Formation and Storage of Feces

  • The transverse colon consolidates and compacts digested material into semi-solid feces by removing water.
  • Temporary storage of fecal material occurs in the transverse colon before it is moved to the descending colon.

Coordination with the Immune System

The transverse colon contains gut-associated lymphoid tissue (GALT), which:

  • Monitors and responds to pathogens in the digestive material.
  • Plays a key role in maintaining a balance between beneficial and harmful microorganisms.

Regulation of Bowel Movements

The transverse colon contributes to the regulation of defecation:

  • As fecal material accumulates, stretch receptors signal the need for mass movements.
  • These movements push material toward the rectum for elimination.

Role in Gas Management

The transverse colon facilitates the segregation of gas (flatus) from fecal material:

Gas, produced by microbial fermentation, is moved toward the rectum, where it can be expelled without the passage of solid waste.[2]

Clinical Significance

The transverse colon is clinically significant as it is a common site for various gastrointestinal disorders due to its anatomical position and functions:

  • Colorectal Cancer: The transverse colon can develop malignant tumors, often presenting with symptoms like altered bowel habits, abdominal pain, and rectal bleeding. Early detection is crucial for management.[4]
  • Volvulus: Although less common than sigmoid volvulus, the transverse colon’s mobility can lead to twisting, causing intestinal obstruction and severe abdominal pain.
  • Diverticulosis: Pouches (diverticula) can form along the transverse colon, especially with chronic constipation, which may lead to inflammation (diverticulitis).
  • Ischemia: The transverse colon is prone to ischemic colitis due to its watershed location between the superior and inferior mesenteric artery blood supplies.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn’s disease and ulcerative colitis often involve the transverse colon, causing inflammation, pain, and diarrhea.

References

  1. Standring, S. (2020). Gray’s Anatomy: The Anatomical Basis of Clinical Practice (42nd ed.). Elsevier. ISBN 978-0702077050.
  2. Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2017). Clinically Oriented Anatomy (8th ed.). Wolters Kluwer. ISBN 978-1496347213.
  3. Borley, N. R. (2005). Last’s Anatomy: Regional and Applied (11th ed.). Churchill Livingstone. ISBN 978-0443103739.
  4. Snell, R. S. (2012). Clinical Anatomy by Regions (9th ed.). Lippincott Williams & Wilkins. ISBN 978-1451110326.
  5. Skandalakis, J. E., Skandalakis, L. J., & Skandalakis, P. N. (2004). Surgical Anatomy and Technique: A Pocket Manual (2nd ed.). Springer. ISBN 978-0387215822.
  6. Williams, N. S., Bulstrode, C. J. K., & O’Connell, P. R. (2018). Bailey & Love’s Short Practice of Surgery (27th ed.). CRC Press. ISBN 978-1498796507.
  7. Johnson, L. R. (2018). Gastrointestinal Physiology (9th ed.). Elsevier. ISBN 978-0323595636.
  8. Schuenke, M., Schulte, E., & Schumacher, U. (2010). THIEME Atlas of Anatomy: General Anatomy and Musculoskeletal System (2nd ed.). Thieme. ISBN 978-1604069228.