Multimodal pain assessment integrates multiple validated tools to comprehensively evaluate the multidimensional pain experience across physiological, behavioral, and self-report domains. The Numeric Rating Scale (NRS 0-10) and Visual Analog Scale provide unidimensional pain intensity measures, while the McGill Pain Questionnaire captures sensory, affective, and evaluative dimensions of pain. For patients unable to self-report, behavioral tools are essential: the FLACC scale (Face, Legs, Activity, Cry, Consolability) for pediatric patients, the PAINAD (Pain Assessment in Advanced Dementia) for cognitively impaired older adults, and the Critical Care Pain Observation Tool (CPOT) for sedated or intubated patients. Pain is mediated by nociceptor activation (A-delta fibers for sharp, localized pain; C fibers for dull, diffuse, burning pain) with signal transmission through the dorsal horn (where gate control theory modulation occurs) to the thalamus and cerebral cortex for pain perception. Multimodal analgesia targets multiple points in the pain pathway: acetaminophen and NSAIDs at the peripheral nociceptor level, regional anesthesia at the nerve conduction level, and opioids at the central modulation level. The nurse selects appropriate assessment tools based on patient characteristics, reassesses pain after each intervention,...