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 (pĕr′ə-no͝or′ē-əm, -nyo͝or′-)
n. pl. per·i·neu·ri·a (-no͝or′ē-ə, -nyo͝or′-)
The sheath of connective tissue enclosing a bundle of nerve fibers.

[New Latin : peri- + Greek neuron, nerve; see neuron.]

per′i·neu′ri·al adj.


n, pl -neuria (-ˈnjʊərɪə)
(Anatomy) the connective tissue forming a sheath around a single bundle of nerve fibres
[C19: from New Latin, from peri- + Greek neuron nerve]
ˌperiˈneurial adj


(ˌpɛr əˈnʊər i əm, -ˈnyʊər-)

n., pl. -neu•ri•a (-ˈnʊər i ə, -ˈnyʊər-)
the sheath of connective tissue that encloses a bundle of peripheral nerve fibers.
[1835–45; < New Latin; see peri-, neur-, -ium2]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.perineurium - the sheath of connective tissue that covers a bundle of nerve fibers
connective tissue - tissue of mesodermal origin consisting of e.g. collagen fibroblasts and fatty cells; supports organs and fills spaces between them and forms tendons and ligaments
References in periodicals archive ?
The clinical administration of peripheral nerve injury is still the classic epineurium or perineurium neurorrhaphy that dates back to more than 100 years ago.
A thickening of the walls of the microvessels in the endoneurium and perineurium has been demonstrated in a few case reports of patients who had nerve segment resection.
As a result, swelling occurs in the in the perineurium which causes ischaemia, fibrosis and axonal death.
1) outlines a mechanism proposed by Ellis (66) to explain thoracic outlet syndrome that suggests that this type of trauma to the nervi nervorum creates a cycle of inflammation within the perineurium that results in an individual nerve "internal compartment syndrome".
Transverse view showing normal speckled fascicular pattern (thin arrow) of ulnar nerve 2 cms below medial epicondyle surrounded by hyperechoic perineurium (thick arrow).
1) Histologically, each peripheral nerve consists of axons, Schwann cells that form myelin sheaths around some axons, endoneurium, perineurium, and epineurium.
In histology analysis, the features shown on the slide collection were observed and described, as the following structures: epineurium, perineurium and endoneurium, nerve fiber, inflammatory infiltrate, Schwann cells, fibroblasts, and blood vessels.
Electron microscopic evaluation of the resected specimens of interdigital neuroma reported edema of the endoneurium, fibrosis beneath the perineurium, axonal degeneration, and necrosis, which suggested nerve damage secondary to mechanical impingement by adjacent structures [27].
It is alleged that the proliferation of schwann cells in the perineurium leads to schwannoma that causes displacement and compression of the adjacent nerve.
When tumor cells invade the perineurium and nerve sheaths, the cranial nerves can essentially provide a direct route of spread toward the base of the skull and intracranial extension.
With axonotmesis, the Schwann cell, the epineurium, and perineurium remain intact.
Endometriosis causes nerve damage by cyclic inflammation and advancing implanted ectopic uterine tissue into the epineurium and perineurium (4).