Meeting Abstract

P3.128  Monday, Jan. 6 15:30  Bent out of shape: Bioinspired vertebral column morphology and mechanics DONATELLI, CM*; SUMMERS, AP; PORTER, ME; University of Rochester; Friday Harbor Labs; Florida Atlantic University cdonatel@u.rochester.edu

Vertebral centra are often characterized by the shape of the anterior and posterior faces, which can be flat, convex or concave. The platycoelus vertebrae of most mammals have flat faces, while the mono- and diphycoelus vertebrae of fishes, reptiles and amphibians have one or two concave faces. Some marine mammals even have slightly convex vertebral faces. There is a strong phylogenetic signal for centrum shape, and we are interested in the functional implications of the intervertebral cavity. We used a rapid prototyper and a viscoelastic molding technique to test the effects of centrum morphology and intervertebral joint length on mechanical outputs of the vertebral column. Five models, inspired by the vertebral morphology of fishes, humans, and marine mammals, were designed and printed. We constructed motion segments (centrum–joint–centrum) of varying joint length for each centrum morphology. Moment arms were added to motion segments to ensure loading in pure bending. From force outputs, we calculated moment (Nm), work (J), and bending stiffness (Nm²). Increasing the bending angle during testing, doubled moment and increased work produced by an order of magnitude, while decreasing bending stiffness by an average of 0.15 Nm². Increasing joint length decreases each of these mechanical properties by three to four times. The slightly convex vertebral face of marine mammal models, regardless of joint length, produced the largest moment, work, and bending stiffness values while the intermediate concave fish model had the lowest. These data suggest that convex and flat models are consistently stiffer than concave models. Our data show the relation between centrum shape, joint length, and their associated mechanical outputs is not linear. This research was funded by NSF grant DBI 1262239.