Quantifying Acoustic Impedance Matching and Pressure Transduction at the Skeletal-Respiratory Interface in Avian Flight

This study develops a quantitative physical model demonstrating that mechanical waves generated within the avian pectoral girdle during flight must couple directly into the internal air sac system. By integrating furcular kinematics, acoustic impedance analysis, and structural analogues from engineered transducers, the work shows that even small skeletal deflections produce internal pressure oscillations far exceeding known visceral mechanoreceptor thresholds. The results support a view of the avian respiratory system as a mechanically responsive structure whose air sacs participate in rapid internal signal transduction rather than serving solely ventilatory roles. Readers working on air sac morphology, pneumaticity, and musculoskeletal–respiratory integration will find a testable framework that links skeletal deformation to intra‑sac pressure dynamics, offering a new direction for investigating the mechanical functions of the avian respiratory apparatus.