Meeting Abstract
In fully aquatic mammals, the axial skeleton is a key anatomical feature powering locomotion. Previous research showed that mechanical behavior of the vertebral column partially mediates body deformation during axial locomotion, and that these behaviors vary regionally. Assessing mechanical properties of vertebral bodies provides insight on how bone of aquatic species responds to forces. The three goals of the present study are to (1) assess mechanical properties, yield strengths (MPa) and elastic moduli (MPa), in the axial plane of vertebral bodies, (2) compare yield strength and elastic moduli taking into account functional location and type of vertebrae, (3) compare mechanical properties of aquatic animals from this study with terrestrial mammalian bone from bovine models. Three vertebrae from the thoracic, lumbar, and caudal regions were sampled the following species: West Indian manatee (Trichechus manatus), common bottlenose dolphin (Tursiops truncatus), and pygmy sperm whales (Kogia breviceps). All soft tissue and bone projecting from the vertebral body were removed with a bone saw and sander. Vertebral bodies were tested under a compressive load at a displacement rate of 2mm/min until the material transitioned from the elastic to plastic region indicating yield. Yield strengths (MPa) were quantified as the maximum stress the vertebral body can withstand before being permanently deformed. Elastic moduli (MPa), the material’s ability to resist compression, were calculated from the linear portion of the stress-strain curve. Density measurements were taken after the mechanical test to give a coarse estimate of microarchitecture of each vertebral body.
