Haustra of colon

The haustra of colon are a series of sacculations or pouch-like bulges that give the large intestine its characteristic segmented appearance. They are formed because the three longitudinal bands of smooth muscle, known as the taeniae coli, are shorter than the length of the colonic wall. This discrepancy causes the wall of the colon to pucker into a series of outward bulges called haustra. Haustra are present throughout the caecum, ascending colon, transverse colon, descending colon, and sigmoid colon, but are absent in the rectum where the taeniae coli spread out to form a continuous longitudinal muscle layer.

Functions

Haustra facilitate the mixing and slow propulsion of colonic contents, promoting the absorption of water and electrolytes and aiding in the formation of faeces.

Clinical correlates

Loss of the normal haustral pattern may occur in chronic inflammatory conditions such as Ulcerative Colitis, producing the characteristic "lead-pipe colon" appearance on radiographic examination.