Assessment of Correlations Between Amplitude of Thoracic and Diaphragmatic Mobility in Healthy Adults

Introduction: Thoracic and diaphragmatic mobility are key components of respiratory mechanics and jointly contribute to effective ventilation. Simple clinical tools, such as tape-based chest expansion measurements and ultrasound assessment of diaphragmatic excursion, are increasingly used in respiratory and physiotherapy practice. However, the physiological relationship between thoracic and diaphragmatic mobility assessed using these methods has not been sufficiently explored. Objectives This study aimed to investigate the association between thoracic mobility measured at different chest levels and diaphragmatic mobility assessed using ultrasonography in healthy adults. Material and methods Thirty healthy adults participated in this cross-sectional study. Thoracic mobility was assessed using tape measurements during maximal inspiration and expiration at three levels: axillary, sternal, and xiphoid. Diaphragmatic mobility was evaluated as diaphragmatic excursion using M-mode ultrasonography. Results Significant positive correlations were observed between diaphragmatic excursion and thoracic mobility at all measured chest levels, with the strongest association at the axillary level (r = 0.53). Age and BMI were negatively associated with both diaphragmatic and thoracic mobility, while no significant sex-related differences were observed. Conclusions These findings support the concept of functional coupling between thoracic and diaphragmatic components of respiratory mechanics.