This work presents LaFountaine Structural Correction (LSC) and its associated Cross-Lateral Hydrotherapy and Thermal Modulation Framework, a systems-level approach designed to support structural correction by modulating nervous system state and tolerance rather than applying force-based or symptom-driven interventions. The framework formalizes the use of simultaneous, cross-lateral opposing thermal inputs (heat and cold), delivered through hydrotherapy and non-immersive thermal modalities, to reduce unilateral threat weighting, decrease protective guarding, and facilitate a neutral regulatory state. Emphasis is placed on central nervous system integration, interoception, autonomic regulation, and tolerance engineering, rather than peripheral vascular cycling or localized tissue effects as primary mechanisms. This publication documents the conceptual lineage from Cross-Lateral Hydrotherapy Modulation (X-LHM) through to the finalized non-immersive implementation Cross-Lateral Thermal Modulation (X-LTM). Detailed procedural logic, placement topology, contraindications, modeled SOAP-based longitudinal analysis, and conservative mechanistic interpretation are provided to support reproducibility and clinical reasoning within appropriate professional scope. All material is presented for educational and professional informational purposes only. No claims of diagnosis, treatment, cure, or disease prevention are made. Physiological explanations are interpretive and grounded in established anatomy, neurophysiology, and systems biology. This work is intended as a regulatory adjunct within structural correction practice and does not replace medical evaluation or care.