English to Portuguese Medical Medical (general)

Within each fascicle lies a longitudinally oriented capillary plexus with loop formations at various levels. The capillary system is fed by arterioles 25 to 150 mm in diameter that penetrate the perineurial membrane. These vessels run an oblique course through the perineurium, and it is believed that because of this structural peculiarity, they are easily closed like valves in the event that tissue pressure inside the fascicles increases (Lundborg, 1975; Myers et al., 1986). Engineering structural analysis of these anastomotic transperineurial blood vessels suggests that moderate elevations in endoneurial pressure compresses these vessels and reduces nerve blood flow. This so-called pathologic valve mechanism is a biomechanical mechanism for nerve ischemia, and has been verified by analysis of serial histologic sections in a moderate endoneurial edematous state caused by application of the local anaesthetic solution 3% 2-chloroprocaine HCL (Myers et al., 1986). This phenomenon may explain why even a limited increase in endoneurial fluid pres sure is associated with a reduction in intrafascicular blood flow.