Perineum :: Perineum (n.) The region which is included within the outlet of the pelvis, and is traversed by the urinogenital canal and the rectum..
Perineurial :: Perineurial (a.) Surrounding nerves or nerve fibers; of or pertaining to the perineurium.
Perineurium :: Perineurium (n.) The connective tissue sheath which surrounds a bundle of nerve fibers. See Epineurium, and Neurilemma..