The
epineurium is the outermost layer of dense irregular
connective tissue surrounding a peripheral
nerve. It usually surrounds multiple
nerve fascicles as well as
blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the
perineurium. In addition to blood vessels which supply the nerve, lymphocytes and fibroblasts are also present and contribute to the production of collagen fibers that form the backbone of the epineurium. In addition to providing structural support, lymphocytes and fibroblasts also play a vital role in maintenance and repair of the surrounding tissues.