This is a multi-center prospective observational study that will capture detailed information about the treatment and long term outcomes of 450 patients with PNI resulting from upper extremity trauma. The study will focus on a young adult population to include individuals ages 18-65. Patients with PNI will be recruited during the hospitalization for initial treatment of the upper extremity injury. Additional patients may be identified during clinic visits for on-going treatment of upper extremity injuries as nerve injuries evolve or upon referral from outside physicians. However, all eligible nerve injuries must be treated within 6 months of the initial upper extremity trauma. Outcomes will be assessed at 3, 6, 12, 18 and 24 months following diagnosis of the nerve injury. All assessments will take place in the clinic and will include a patient interview and a brief exam to evaluate sensory and motor function.