Meeting Abstract

P1.151  Monday, Jan. 4  Bending Strain at Intervertebral Joints and Centra in the Cartilaginous Vertebral Columns of Squalus acanthias STURM, J.J.*; LONG, J.H.; PORTER, M.E.; Vassar College; Vassar College; Vassar College josturm@vassar.edu

Vertebral columns are usually modeled with infinitely rigid skeletal elements and flexible, spring-like joints. By treating the vertebrae as elements with infinite stiffness, however, their possible contribution to the overall elastic behavior of the vertebral column is ignored. With this in mind, we model the joints and vertebrae together as a series of Kelvin-Voigt viscoelastic elements. To determine the relative mechanical contributions of each element to the behavior of the column, we measured axial strain of the joints and vertebrae during dynamic bending of an in vitro column segment preparation. We tested vertebral column from six sharks using segments of ten centra. Dynamic testing frequencies ranged from 0.25 to 3.0 Hz at various curvatures on an MTS Tytron 250. Displacement of the joint and centra were measured using sonomicrometry crystals placed bilaterally on the vertebral column at the cranial and caudal surfaces of the central joint and on the centra. Each test was conducted in an environmental chamber in which the vertebral column was submerged in room temperature elasmobranch Ringers solution. We found differences in joint strain with varying curvature. Strain of the vertebrae was less than that of the joints. This work was supported by NSF DBI-0442269 and IOS-0922605.