Biomechanics of the Spinal Cord and the Pia Mater

Abstract

Biomechanical analysis of the spinal cord is important to clarify the morphological plasticity of the spinal cord. In the present study, the elastic moduli of the gray and white matter were measured in situ by using a pipette aspiration method. The mechanical properties and function of the pia mater were investigated. Furthermore, the effect of the tensile stress on the morphology of the spinal cord was investigated. No significant difference in elastic moduli was observed between the gray and white matter of spinal cord. The elastic modulus of the pia mater was 2,300 kPa, which was 460 times higher than that of the spinal cord parenchyma. The pia mater triples the elastic modulus of the spinal cord covered by it compared with the parenchyma and increases the overall stiffness of the spinal cord. As a result of being tightly covered by the pia mater, the compressed spinal cord contains a large amount of strain energy, which enables shape restoration after decompression. The length of the spinal cord was decreased by 9.7 % after the separation to remove longitudinal tensile stress. The tensile stress along the craniocaudal axis in the spinal cord did not affect the spinal cord deformation in response to the compression, but it did affect the shape recoverability after the decompression.