HAUSTRAS: HISTOLOGY, MOTILITY, ASSOCIATED DISEASES - ANATOMY AND PHYSIOLOGY - 2025

The haustras are external bulges of the wall of the colon. The human colon measures approximately 100-150 cm in length and is characterized by having three external longitudinal bands of muscle tissue called "colon tapeworms."

Tapeworms, which are shorter than the entire length of the colon, “pucker” or “pucker” it, forming regular bumps that protrude externally along the entire length of the colon (except for the rectum) and are called haustras.

Image of an open section of the colon showing the haustra and semicircular folds (Source: Internet Archive Book Images via Wikimedia Commons)

The colon is part of the digestive system. It is the portion of the digestive tract that follows the ileum and ends with the rectum at the anal opening. It has a horseshoe shape and several segments are distinguished: the ascending, transverse, descending, and sigmoid colon.

The ascending and descending colon is retroperitoneal and the transverse and sigmoid colon is intraperitoneal. The wall of the large intestine consists of a mucous layer, a submucosa, a double muscular layer and, depending on their peritoneal relationship, a serous and subserous or adventitia.

In addition to being thicker and shorter than the small intestine, the external appearance of the colon differs from the small intestine by three typical formations: tapeworms, haustras, and epiploic appendages.

The fundamental function of the colon is the reabsorption of water, sodium and some minerals. Of the 1000 to 2000 ml of chyme that enters the colon daily from the ileum, he converts it into 200-250 ml of semisolid fecal matter.

Histology

The colon is devoid of villi, but contains abundant crypts of Lieberkühn, similar to those of the small intestine. Goblet cells increase as we approach the sigmoid from the cecum. However, the absorption cells are the most numerous.

The mitotic regeneration cycle is very fast. Every seven days the epithelial lining of the crypts is replaced. The lamina propria, the muscularis mucosae, and the submucosa of the colon are similar to those of the small intestine.

Tapeworms of the colon, haustra, and epiploic appendages

The outer muscular layer of the colon has a very particular distribution. It is somewhat irregular, as it does not cover the entire external surface of the skin, but forms thick bands of longitudinal smooth muscle tissue grouped into three thick and narrow strips called "colon tapeworms."

The constant tone of the tapeworms and their length shorter than the total length of the colon causes it to pucker up and generate sacculations, which are the characteristic haustra. Each tapeworm is about 8 mm wide and is named after its topographic location related to the transverse colon:

- The first tapeworm is called mesocolic tapeworm, it has a dorsomedial position in the transverse colon and in the ascending and descending portions.

- The second is called epiploic tapeworm, since it coincides with the junction site of the greater omentum with the transverse colon; it has a dorsolateral position in the other two segments.

- The third is called free tapeworm, since it is not related to any mesenteric or epiploic union. It runs in the lower portion of the transverse colon and in the anterior aspect of the other two segments.

The sacculations or haustras can be more or less prominent, depending on the degree of contraction of the tapeworms, so that they almost disappear when the complete relaxation of these occurs. The haustras are separated by circular narrowings.

In correspondence with these grooves or narrowings, the mucous membrane of the colon forms transverse folds in the shape of a crescent, which are called "semilunar folds". These folds include in their formation the circular muscle layer. Finally, the serosa is observed, which forms bags full of fats that are called "epiploic appendages".

Motility

At the junction of the ileum with the colon there is a valve called the ileocecal valve. In that valve, the ileum projects slightly into the colon, such that when the pressure in the colon increases, the valve tightens and when the pressure in the ileum increases, the valve opens.

This valve system prevents the reflux of the contents of the large intestine into the ileum when contraction of the colon occurs. Normally, the valve remains closed and opens briefly when a peristaltic wave arrives from the small intestine.

The gastro-ileal reflex that occurs when the stomach empties relaxes the cecum and opens the valve, allowing the passage of chyme to the large intestine.

There are three types of movements in the colon: segmentation movements, peristaltic movements, and mass action contraction. The frequency of the contraction waves ranges from 2 per minute in the cecum to 6 per minute in the sigmoid.

Segmentation movements mix the content and promote absorption. These movements are due to the contraction of tapeworms and circular fibers. Consequently, some haustras distend and others empty.

Peristaltic movements push the intestinal contents toward the rectum. Mass action movements generate powerful contractions throughout large parts of the large intestine.

These contractions move large masses of material within the colon into the rectum, which is consequently distended. The distention of the rectum triggers the defecation reflex.

Diseases that alter the haustra

Loss of the radiological image of the haustra is a radiological sign that usually accompanies chronic ulcerative colitis. This disease is a long-standing chronic pathology consisting of ulceration and inflammation of the colon and rectum.

X-ray contrast image of a patient with a large bowel obstruction (Source: James Heilman, MD via Wikimedia Commons)

The primary symptoms of active disease are abdominal pain and bloody diarrhea. In addition, you may have weight loss, fever and, in some severe episodes, anemia. Typically, symptoms appear intermittently with symptom-free periods alternating with flowery symptoms.

The most frequent complications are megacolon and inflammation of the joints and liver, and some authors have linked it to colon cancer.

Another pathology that can alter the haustra, in this case locally distend some segments of the colon, is intestinal obstruction. In this case, distended haustra segments can be seen on an abdominal radiographic image.

In the sigmoid volvuli that occur more frequently in psychiatric patients, as well as in patients with neurological problems such as Parkinson's disease, an absence of haustras is seen on abdominal radiographs from the pelvis to the right upper quadrant just below the pelvis. diaphragm.

References

1. Ganong, WF, & Barrett, KE (2012). Ganong's review of medical physiology. McGraw-Hill Medical.
2. Gartner, LP, & Hiatt, JL (2012). Color atlas and text of histology. Lippincott Williams & Wilkins.
3. Hall, JE (2015). Guyton and Hall textbook of medical physiology e-Book. Elsevier Health Sciences.
4. Kasper, DL, Hauser, SL, Longo, DL, Jameson, JL, & Loscalzo, J. (2001). Harrison's principles of internal medicine.
5. Netter, FH (1983). The ClBA Collection of Medical Illustrations, Vol. 1: Nervous System, Part II. Neurologic and Neuromuscular Disorders.