Perineurium

The perineurium is the middle layer of nerve sheaths, or cell line of fibers, which consists of thin elongated cells and interstitial connective tissue between them. The main function of this layer is to mechanically protect the fiber from the effects of mechanical environmental disturbances such as pressure, strain and sharp turns, but it also has a certain insulating function, limited to the area of ​​the axon ends and thermally protected from overheating.