| Perineurium (n.) The connective tissue sheath which surrounds a bundle of nerve fibers. See Neurilemma. Thesaurus Entries allantoic membrane, amniotic sac, arachnoid membrane, basement membrane, conjuctiva, eardrum, hymen, maidenhead, membrana serosa, membrana tympana, membrane, meninges, meninx, neurilemma, pellicle, pericardium, perineurium, pleura, serosa, tympanic membrane, tympanum, velum |