Lumen (anatomy)

Overview
A lumen (Lat. lūmen, an opening or light) (pl. lumina) is an inner space, lining or cavity.


 * The interior of a vessel within the body, such as the small central space in an artery or vein, or any of their relating vessels through which blood flows.


 * The inner membrane space of a Thylakoid, endoplasmic reticulum, Golgi apparatus, or microtubule.

On a larger scale it may refer to

 * The interior of the gastrointestinal tract
 * The pathways of the bronchi in the lungs
 * The interior of urinary collecting ducts
 * The single pathway of the vagina