Answer:
the inward district of an organ or tissue, particularly when it is unmistakable from the external area or cortex (as in a kidney, an adrenal organ, or hair).
"the adrenal medulla produces adrenaline"
What do legal researchers involve this for? Scientific researchers might search for the presence or nonappearance of a medulla, which is a bunch of cells that goes through a hair. The medulla is ordinarily unique relying upon the species that the hair came from, which makes it one method for recognizing creature and human hair.