The peripheral nerve is a fundamental biological element that puts the central nervous system in contact with its environment and therefore, its role is key for the individual’s survival. Thanks to the peripheral nerves we have the ability to capture the sensorial stimuli, both external and internal and we can also move voluntarily or react reflexively to protect ourselves from the threats that surround us. Without the peripheral nerves we would be prisoners inside the body. This text presents basic concepts in a clear, integrated and updated way, providing bases to understand the form, normal function, pathophysiology and evaluation mechanisms of the peripheral nerve. In each chapter, graphs are presented to facilitate the follow-up of the text and consolidation of key concepts presented in it.