Anatomically, growth and development of every organ system characterizes infancy and childhood and affects emergency care across the life span. A relatively large occiput, small jaw, high and anterior larynx, narrow cricoid cartilage, and large tongue require unique considerations in airway management (see chapter titled "Pediatric Airway Management"). A soft, compliant chest wall, obligate nose breathing, and gastric inflation from swallowed air alter the mechanics, symptoms, and signs of respiratory distress in young children. Neonates, infants, and children increase cardiac output through an increase in heart rate rather than stroke volume. Tachypnea, an increased rate of breathing, not hyperpnea, an increased depth of respiration, is the primary respiratory compensatory mechanism. The musculoskeletal system of young children differs from that of older children and adults not only in its proportions (e.g., relatively large head), but also because ligaments are stronger than bones, predisposing to fractures rather than sprains. Linear growth of long bones occurs from specialized cartilaginous end plates (physes), which results in unique fracture patterns (see chapter titled "Musculoskeletal Disorders in Children").