Narrowing of Lumen in the Intestines

The lumen is the opening inside a tubular body structure that is lined by body tissue known as an epithelial membrane. Examples of body structures that have a lumen include the large intestine, small intestine, veins, and arteries.

The name comes from the Latin lūmen, one meaning of which is “light.” This is probably because the lumen is an opening inside a tube, and light will pass through a tube.

Small Intestinal Wall


The size of the lumen in the intestine might be measured in order to determine if the intestinal walls are thickening. When the walls of the intestine thicken and cause the lumen to become narrower, it can lead to problems such as strictures (narrowed parts of the intestine).

Intestinal Lumen

In the intestines, the lumen is the opening inside the bowels. It is surrounded by the other parts of the intestinal wall: the mucosa, the submucosa, the muscularis, and the serosa.

In order for food to pass through the intestines, the lumen must be clear, open, and free from any structural problems that can cause an obstruction. In people with inflammatory bowel disease (IBD), the lumen might be affected.

IBD goes through periods of active disease and remission. In times of active disease, there is inflammation that affects the surface layer (mucosal layer) of the intestine, which can cause ulcers. As the disease is managed and the ulcers on the inner intestinal wall heal over in places, scar tissue may form.

The repeated cycle of inflammation and healing can build up the scar tissue to the point where it results in a thickening of the wall of the bowel.

When the Lumen Starts to Become Narrowed

Scar tissue is not as flexible as regular tissue, and therefore it behaves differently. When there is scar tissue in the intestine, the lumen is affected, and it may become narrowed or obstructed (blocked).

The narrowed part of the lumen is called a stricture. The waste material can’t pass through the lumen easily, which can lead to pain, bowel obstructions, or other complications.

Strictures tend to be more commonly associated with Crohn’s disease than with ulcerative colitis, however they can occur in both forms of IBD.

The reason for this is that Crohn’s disease can occur anywhere in the digestive tract from the mouth to the anus, and can affect several layers of the bowel wall. Ulcerative colitis usually affects only the large intestine and the rectum, and the inflammation it causes is generally confined to the surface mucosal layer.

In Crohn’s disease, strictures tend to be in the small intestine, and in ulcerative colitis, strictures tend to be in the rectum.

Strictures can be very troublesome for people with IBD because they block food from moving through the bowels. With strictures that are very narrow, food begins to back up in the bowel. This could lead to a bowel obstruction, and there could be symptoms of pain, vomiting, diarrhea, or constipation.

In some cases, obstructions can be treated in the hospital with a nasogastric (NG) tube and other methods, but some strictures are advanced enough that they require surgery. Without surgery, the obstructions may keep occurring.

3 Sources
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  1. Chang CW, Wong JM, Tung CC, Shih IL, Wang HY, Wei SC. Intestinal stricture in Crohn’s diseaseIntest Res. 2015;13(1):19–26. doi:10.5217/ir.2015.13.1.19

  2. Parray FQ, Wani ML, Malik AA, et al. Ulcerative colitis: a challenge to surgeonsInt J Prev Med. 2012;3(11):749–763.

  3. D’Incà R, Caccaro R. Measuring disease activity in Crohn’s disease: what is currently available to the clinicianClin Exp Gastroenterol. 2014;7:151–161. doi:10.2147/CEG.S41413

Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.