Definition of Lumen
Lumen: A luminous term referring to the channel within a tube such as a blood vessel or to the cavity within a hollow organ such as the intestine. Lumen is a luminous term because it is Latin for light, including the light that comes through a window. When a hollow organ is cut across, you can see light through the space that has been opened. So the word "lumen" came to mean this space.
For example, in arteriosclerosis, fat deposits narrow the lumen of the artery. For another example, cells called enetrocytes within the intestinal wall help transport water from the lumen of the intestine into the bloodstream.
Last Editorial Review: 10/9/2012
Back to MedTerms online medical dictionary A-Z List
Need help identifying pills and medications?
Get the latest health and medical information delivered direct to your inbox FREE!