Main Entry: peri·neu·ri·um Pronunciation: "per-&-'n(y)ur-E-&m Function: noun Inflected Form: pluralperi·neu·ria/-E-&/ : the connective-tissue sheath that surrounds a bundle of nerve fibers
perineurium per·i·neu·ri·um (pěr'ə-n&oobreve;r'ē-əm, -ny&oobreve;r'-) n.pl.per·i·neu·ri·a (-n&oobreve;r'ē-ə, -ny&oobreve;r'-) The sheath of connective tissue enclosing a bundle of nerve fibers.