A three-dimensional structural analysis model of the human thoracolumbar spine and rib cage has been developed in order to investigate its stability in relation to adolescent idiopathic scoliosis. Idiopathic scoliosis is one of the most puzzling deformities of the spine, due to the fact that there is no known initiating cause. From the viewpoint that it can be explained in a purely biomechanical manner, one particular hypothesis as to its etiology is investigated in this thesis. The hypothesis is that a lordosis-inducing growth of the thoracic spine [34,100,115] in conjunction with spinal asymmetries in the lateral or horizontal plane [34] is the primary cause of the deformity. / Analyses are performed on the constructed model using the MSC/NASTRAN finite element program. The model consists primarily of interconnected beam elements to represent a realistic geometry of the spine and rib cage. The various stiffness properties needed in the model were obtained from the published literature. Simulations of analyses and experiments performed by other researchers produced comparable results, thereby validating the present model, which is then used to investigate the above hypothesis. / Lordosis-inducing growth, in which the anteriors of the thoracic vertebrae grow faster than the posteriors, is simulated in a geometric nonlinear analysis by differential thermal loading of these parts. Results show that under such loading, the model of the normal spine with its natural asymmetries of the thoracic region, gradually deforms into a shape with displacements and rotations typical of thoracic idiopathic scoliosis. These results therefore constitute a validation of the stated hypothesis, and indicate that a lordosis-inducing growth of the thoracic vertebrae is a likely cause of thoracic idiopathic scoliosis.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20139 |
| Date | January 1992 |
| Creators | Reimbold, Micheline. |
| Contributors | Shnvastava, S. C. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Civil Engineering and Applied Mechanics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001657564, proquestno: MQ44102, Theses scanned by UMI/ProQuest. |
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