Definition of perineurium in US English:



  • The sheath of connective tissue surrounding a bundle (fascicle) of nerve fibers within a nerve.

    • ‘In these lesions, the hyphae appeared to invade the perineurium, the loose fascial sheath surrounding the nerve.’
    • ‘It strongly stained the perineurium but did not stain the nerve fibers within the perineurium, thus giving a ringlike staining pattern.’
    • ‘Briefly, the nerve fibers were closely packed in the nerve bundles in the endoneurial areas surrounded by the perineurium and the epineurium.’
    • ‘However, in most of the smaller fibers the space between nerve and perineurium was reduced or absent, so that it could not be established whether the peripheral staining represented nerve fibers or perineurium.’
    • ‘The endoneurium is continuous with the more abundant connective tissue perineurium, which envelops bundles of nerve fibers.’
    covering, cover, case, casing, envelope, sleeve, wrapper
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Mid 19th century: modern Latin, from Greek peri- ‘around’ + neuron ‘sinew’.