[1]In biology, a lumen (pl.
: lumina) is the inside space of a tubular structure, such as an artery or intestine.
[2] It comes from Latin lumen 'an opening'.
It can refer to: In cell biology, lumen is a membrane-defined space that is found inside several organelles, cellular components, or structures, including thylakoid, endoplasmic reticulum, Golgi apparatus, lysosome, mitochondrion, and microtubule.
Transluminal procedures are procedures occurring through lumina, including:[citation needed] This anatomy article is a stub.