- 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.
* * *1. The space in the interior of a tubular structure, such as an artery or the intestine. 2. (lm) The unit of luminous flux; the luminous flux emitted in a unit solid angle of 1 steradian by a uniform point source of light having a luminous intensity of 1 candela. 3. The volume enclosed within the membranes of a mitochondrion or of the endoplasmic reticulum. 4. The bore of a catheter or hollow needle. [L. light, window]
* * *1) the cavity of a tubular organ <the \lumen of a blood vessel>2) the bore of a tube (as of a hollow needle or catheter)3) a unit of luminous flux equal to the light emitted in a steradian by a uniform point source of one candle intensity
* * *n.1. the space within a tubular or sac-like part, such as a blood vessel, the intestine, or the stomach.2. the SI units of luminous flux, equal to the amount of light emitted per second in unit solid angle of 1 steradian by a point source of 1 candela. Symbol: lm.
* * *lu·men (looґmən) pl. luґmina, lumens [L. â€œlightâ€] 1. the cavity or channel within a tube or tubular organ. 2. the SI unit of luminous flux; it is the light emitted in a solid angle of 1 steradian by a uniform point source with luminous intensity of 1 candela. Abbreviated lm.
Lumen of coronary artery, moderately narrowed by atheromatous plaque.
Medical dictionary. 2011.