Meeting Abstract

P3.138  Sunday, Jan. 6  Rib kinematics during ventilation in Alligator mississippiensis MORITZ, S.; Brown University sabine_moritz@brown.edu

Lung ventilation in crocodylians is accomplished by a hepatic piston mechanism driven by the m. diaphragmaticus combined with costal and pelvic movements. While the diaphragmatic mechanism is well studied, less attention has been paid to the contribution of costal movements to ventilation. In this study, marker-based X-ray Reconstruction of Moving Morphology (XROMM) was used to analyze rib movements during breathing in American alligators. Spherical metal markers were surgically implanted into the tripartite ribs, the sternum and the dorsal scutes of juvenile alligators. Biplanar x-ray recordings of standing and walking alligators were recorded and ct-scans of the same individuals were taken. By combining both data sets, 3D animations of rib motion during ventilation were created and rib kinematics analyzed. Preliminary results show that rib movements support ventilation both in standing and walking alligators. Rib movements result in dorso-ventral flattening of the rib cage during exhalation and expansion during inhalation. The largest movements occur in the sternal part of the rib, whereas intermediate and vertebral ribs only show small movements. The kinematic data will be combined with EMG recordings to infer the function of the intercostal musculature during ventilation.