GENERATION OF A 3-D PARAMETRIC SOLID MODEL OF THE HUMAN SPINE USING ANTHROPOMORPHIC PARAMETERS A thesis presented to the faculty of the Fritz J. and Dolores H. Russ College of Engineering and Technology of Ohio University In partial fulfillment of the requirements for the degree Master of Science Douglas P. Breglia June 2006 This thesis entitled GENERATION OF A 3-D PARAMETRIC SOLID MODEL OF THE HUMAN SPINE USING ANTHROPOMORPHIC PARAMETERS by DOUGLAS P. BREGLIA has been approved for the Department of Mechanical Engineering and the Russ College of Engineering and Technology by Bhavin Mehta Associate Professor of Mechanical Engineering R. Dennis Irwin Dean, Russ College of Engineering and Technology Abstract BREGLIA, DOUGLAS P., M.S., June 2006. Mechanical Engineering GENERATION OF A 3-D PARAMETRIC SOLID MODEL OF THE HUMAN SPINE USING ANTHROPOMORPHIC PARAMETERS (98 pp.) Director of Thesis: Bhavin Mehta It has been shown that there is a correlation between stature and the dimensions of the vertebra in humans [1]. The objective of this thesis is to create a computer model of the vertebra that is personalized based on external metrics. To accomplish this, a parametrically linked solid model of the vertebrae is linked to the height, sex, and ethnicity of an individual. Vertebral morphologies presented in the literature are used to create geometric primitives of each bone. Relationships from forensic science are used to relate an individual’s stature to the heights of each of the vertebrae. Also, relationships between the vertebral height and the other dimensions of the vertebra are derived. These together can be used to create a model of each vertebra that is modified according to external human parameters. This model creates a simple and fast tool for the creation of personalized vertebral models. Approved: Bhavin Mehta Associate Professor of Mechanical Engineering 4 Table of Contents Page Abstract .......................................................................................................................................................................... 3 List of Tables .......................................................................................................................................................... 6 List of Figures......................................................................................................................................................... 7 1. Introduction......................................................................................................................................................... 8 1.1. The Human Body and Bio-Engineering ...................................................................................................... 8 1.3. The Spine: Anatomy and Function ............................................................................................................ 11 1.3.1. Sections of the Spine........................................................................................................................... 12 1.3.2. The Vertebra ....................................................................................................................................... 14 1.4. Forensic Osteology .................................................................................................................................... 18 1.5. Medical Imaging ........................................................................................................................................ 18 1.6. Statement of Thesis.................................................................................................................................... 20 1.7. Thesis Objectives....................................................................................................................................... 20 2. Literature Review.............................................................................................................................................. 22 2.1. Modeling the Spine and Vertebrae ............................................................................................................ 22 2.1.1. Whole Spine Models........................................................................................................................... 22 2.1.2. Vertebral Models ................................................................................................................................ 23 2.1.3. Intervertebral Disc, Lumbar, and Cervical Models ............................................................................ 24 2.1.4. Spinal Mobility - Condition and Instrumentation............................................................................... 26 2.2. Methods to Obtain a Model ....................................................................................................................... 26 2.3. External/Internal Parameter Matching....................................................................................................... 28 3. Methodology..................................................................................................................................................... 32 3.1. Software ..................................................................................................................................................... 32 3.2. Obtaining Data........................................................................................................................................... 32 3.3. Determination of Spinal Parameter Relationships..................................................................................... 38 3.3.1. Spinal Curve........................................................................................................................................ 38 3.3.2. Spinal Height and Vertebral Body Heights ........................................................................................ 40 3.3.3. Disc Heights........................................................................................................................................ 41 3.4. Determination of Vertebral Parameter Relationships................................................................................ 43 3.4.1. Distance Method & Area Method....................................................................................................... 45 3.4.2. Angular Parameters............................................................................................................................. 45 3.4.2.1. Endplate Inclination..................................................................................................................... 45 3.4.2.2. Articular Facet Angles ................................................................................................................. 47 3.4.2.3. Pedicle Inclination ....................................................................................................................... 48 3.4.3. Poor Correlation Parameters............................................................................................................... 49 3.5. Creating a Solid Model of a General Vertebra .......................................................................................... 52 3.5.1. Vertebral Body Model ........................................................................................................................ 54 3.5.2. Vertebral Arch Model......................................................................................................................... 56 3.6. Spinal Curve Model ................................................................................................................................... 64 3.7. Final Assembly of the Model..................................................................................................................... 67 4. Results and Conclusions ................................................................................................................................... 70 5 4.1. The Spinal Model....................................................................................................................................... 70 4.2. Conclusions................................................................................................................................................ 75 References............................................................................................................................................................. 77 Appendix A........................................................................................................................................................... 84 Appendix B ........................................................................................................................................................... 85 Appendix C ........................................................................................................................................................... 86 Appendix D........................................................................................................................................................... 87 Appendix E ........................................................................................................................................................... 88 Appendix F...........................................................................................................................................................