- Pertaining to being between things, especially between things that are normally closely spaced. The word "interstitial" comes from the Latin "interstitium" which was derived from "inter" meaning "between" + "sistere" meaning "to stand' = to stand between. The word "interstitial" is much used in medicine and has specific meaning depending on the context. For instance, interstitial cystitis is a specific type of inflammation of the bladder wall. Interstitial radiation involves placing radioactive material directly into a tumor. Interstitial pneumonia is inflammation of the lung which involves the meshwork of lung tissue (alveolar septa) rather than the air spaces (alveoli).
* * *1. Relating to spaces or interstices in any structure. 2. Relating to spaces within a tissue or organ, but excluding such spaces as body cavities or potential space. Cf.:intracavitary.
* * *in·ter·sti·tial .int-ər-'stish-əl adj1) situated within but not restricted to or characteristic of a particular organ or tissue used esp. of fibrous tissue2) affecting the interstitial tissues of an organ or part <\interstitial hepatitis>3) occurring in the part of a fallopian tube in the wall of the uterus <\interstitial pregnancy>in·ter·sti·tial·ly -ə-lē adv
* * *in·ter·sti·tial (in″tər-stishґəl) pertaining to or situated between parts or in the interstices of a tissue.
Medical dictionary. 2011.