The PNS is comprised of all cranial and spinal cord nerves and their ganglions. Every nerve is composed of thousands of small cables (axons). These axons are responsible for transmitting information along the nerve. Whenever a lesion occurs on a peripheral nerve, the damaged part is the axon, which unlike the neuronal body presents a certain regenerative capacity.
This section concentrates on the nerves originating in the spinal cord as pathologies affecting cranial nerves are discussed in other sections.

The pathologies affecting the PNS can be differentiated as:

Traumatic, such as the severing of a nerve.
Degenerative such as the compression of nerves at some point of their length such as Carpal tunnel syndrome.