Basic pathology of the peripheral nervous system

The human peripheral nervous system (PNS) is a highly complex structure. A large and growing number of hereditary and non-hereditary lesions are known to cause peripheral neuropathy. Nevertheless, in certain diseases a biopsy of a segment of a single nerve can provide an accurate diagnosis. Structural changes of the PNS may affect any of its various components. These include peripheral motor, sensory, and autonomic neurons and their axons, as well as Schwann cells and myelin sheaths in the radicular and peripheral nerves. The connective tissue components of the endoneurium, perineurium, and epineurium, including blood and lymphatic vessels may also be affected, either primarily or secondarily.