Non-Anesthetized Plexus Technique for Infant (BPBP) MRI Evaluation

Inclusion Criteria: * Diagnosis of brachial plexus birth palsy. * Age at consent ≤4 months Exclusion Criteria: * Bilateral brachial plexus birth palsy. * Age at MRI \<28 days or \>4 months old (patients can be enrolled prior to 28 days of age, but the imaging must occur in the 28 days to 4 months' time period). The lead PI will need to approve the enrollment of a subject who will have the MRI after 90 days of age. * Concomitant medical conditions that would preclude performance of or confound interpretation of MRI or any clinical assessment.