Elasticity of the spinal cord, pia, and denticulate ligament in the dog

The longitudinal elasticities of the dog spinal cord, pia, and denticulate ligaments were obtained by measuring the load-elongation curves. Both pia and denticulate ligaments were moderately elastic, but the spinal cord substance showed an upward curve, which indicated a predominantly viscous character. In situ, the spinal cord and pia were moderately strained. A 40-mm segment of the cord with dorsal and ventral roots severed and denticulate ligaments removed became 1 mm shorter when the cord and pia were transected at both ends. It was estimated that the cord and pia in situ were stressed by a force of 2 to 3 gm, the denticulate ligaments with 3 to 5 gm, and the dura with 50 to 70 gm. The elastic moduli of the spinal cord substance were 1.68 X 10(5) dynes/sq cm for loading between 5 and 10 gm and 1.19 X 10(5) dynes/sq cm between 30 and 35 gm.