XROMM analysis of rib kinematics during lung ventilation in the green iguana, Iguana iguana

摘要: The three-dimensional rotations of ribs during breathing are typically described as bucket-handle rotation about a dorsoventrally oriented axis, pump-handle mediolateral and caliper rostrocaudal axis. In amniotes with double-headed ribs, rib motion is constrained primarily to one degree-of-freedom (DOF) an axis connecting the two articulations. However, in Squamata, single headed hemispherical costovertebral joints permit three DOF. this study, we used X-ray reconstruction moving morphology (XROMM ) quantify deep four green iguanas. We found that was strongly dominated by rotation, thus exhibiting nearly hinge-like motion, despite potential for more complex motions. vertebral sternal segments each did not deform measurably breathing, but they move relative other at thin, cartilaginous intracostal joint. While standing still deeply, individual iguanas showed variability their postures, around highly inflated posture, posture folded halfway back. Bucket-handle clear gradients, increasing from third cervical first or second dorsal rib, then decreasing again caudally, pattern consistent intercostal muscles rostral spaces being primary drivers inspiration. constrained, observed here do help explain evolution permissive, squamates articulations amniotes.