This chapter provides a comprehensive examination of the respiratory system’s anatomical organization, with particular emphasis on structural relationships and functional integration. The respiratory tract is systematically described from the upper airways through the tracheobronchial tree to the terminal respiratory units. The chapter details the complex architecture of the pharynx and larynx, emphasizing their dual roles in respiration and protection of the lower airways. The tracheobronchial tree’s branching patterns and regional variations are explored, emphasizing their clinical significance in respiratory medicine and surgical interventions. The chapter presents a detailed analysis of pulmonary segmental anatomy, describing the asymmetric organization between right and left lungs and its clinical implications. The bronchopulmonary segments are examined in detail, with emphasis on their three-dimensional relationships and surgical relevance. The pleural anatomy and its mechanical significance in respiratory function are discussed, along with the complex neurovascular relationships of the respiratory system. A significant portion focuses on respiratory muscles, particularly the diaphragm’s structure and function as the primary respiratory muscle. The coordinated actions of external and internal intercostal muscles, along with accessory respiratory muscles, are described in the context of both quiet breathing and forced respiratory maneuvers. The biomechanics of thoracic cage movement during respiration is explored, detailing the “bucket-handle” and “pump-handle” movements of different rib groups. The chapter concludes with an examination of autonomic innervation of the respiratory system, describing both sympathetic and parasympathetic pathways and their roles in regulating airway tone, secretion, and vascular function. The integration of respiratory mechanics in speech production is also addressed, highlighting the relationship between respiratory function and vocal mechanisms. Throughout, the chapter emphasizes on clinical correlations, particularly in relation to respiratory pathology and therapeutic interventions in respiratory care for individuals with spinal cord injuries. The text integrates current understanding of respiratory anatomy with functional considerations, providing a foundation for clinical practice in spinal cord medicine, rehabilitation medicine, and related specialties.