Upper extremity nerve injury can be due to multiple causes and has a constellation of effects depending on the site, method, and, if applicable, injected substance. While many injuries result from mechanical etiologies such as needles for vaccines and nerve blocks, secondary chemical injury may occur, usually presenting with a different set of symptoms and timeline. Management of such injuries is tiered as well, ranging from conservative measures—physiotherapy and analgesics—to surgical neurolysis. Injury avoidance is paramount; preventative measures are possible for many of the more common etiologies of upper extremity nerve injuries. The purpose of this paper is to assemble etiologies, signs and symptoms, diagnosis, and management of the most common nerve injuries of the upper extremity.