Neurolemma (spelled also neurolema, neurilemma and neurilema, and used interchangeably with epineurium) is the insulating myelin layer that surrounds an individual peripheralnerve fiber. The myelin is contributed by Schwann cells and the layer is sometimes referred to as the sheath of Schwann. The neurolemma is instrumental in regenerating axons that have been injured. In neuroscience, myelin is an electrically insulating fatty layer that surrounds the axons of many neurons, especially those in the peripheral nervous system. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ... Schwann cells are a variety of neuroglia that wrap around axons in the peripheral nervous system, forming the myelin sheath. ...
From the outside inward these are the mesoneurium, epineurium, perineurium, and endoneurium (Daniel & Terzis 1977, May 1986, Millesi & Terzis 1987, Lundborg 1988).
The epineurium is the loose connective tissue sheath that defines the nerve trunk and protects it against mechanical stress.
Traction and compression are the usual mechanisms of this type of injury and may cause severe ischemia, intrafascicular edema, or demyelination.