This chapter focuses on the intricate pathologies and anatomical structures related to peripheral nerves and skeletal muscles. It explores various conditions such as carpal tunnel syndrome, dermatomyositis, and myofibrillar myopathies, providing insights into their mechanisms, diagnosis, and management. The chapter delves into the role of cranial nerves and nerve plexuses, including the impact of neurofibromatosis type 1 and Parsonage–Turner syndrome on nerve function. The importance of dermatomes, including lumbosacral dermatomes, is discussed in relation to peripheral neuropathies and musculoskeletal disorders. The structural components of muscles, such as the epimysium, perimysium, and sarcolemma, are examined, with a focus on diseases such as facioscapulohumeral dystrophy (FSHD) and imaging techniques in neuropathy diagnosis. Additionally, the chapter covers pathologies such as ulnar nerve schwannomas, trabecular bone changes, and the histological analysis of fascicles. This comprehensive examination provides a vital understanding of disorders affecting peripheral nerves and muscles.