Peripheral Nerve Structure

A peripheral nerve structure consists of bundles of nerve fibers surrounded by connective tissue. The outside layer of this tissue is called the "epineurium," which is very dense. Each bundle of nerve fiber (fascicle) is, in turn, enclosed in a sleeve of less dense tissue called the "perineurium." The individual nerve fibers are surrounded by a small amount of loose connective tissue, which is called "endoneurium." Blood vessels usually are found in the epineurium and perineurium, which give rise to a network of capillary vessels in the endoneurium.