endoneurium en·do·neu·ri·um (ěn'dō-n&oobreve;r'ē-əm, -ny&oobreve;r'-)
n. pl. en·do·neu·ri·a (-n&oobreve;r'ē-ə, -ny&oobreve;r'-)
The delicate connective tissue enveloping individual nerve fibers within a peripheral nerve. Also called Henle's sheath.