The morphology of the zygapophyseal joint in relation to biomechanical properties

number: 
1656
English
Degree: 
Author: 
Summer Sarmed Mahmood Mukhtar
Supervisor: 
Dr. Sadiq J. Abbas
Dr.Akram Abood Jaffar
year: 
2007

Abstract : Zygapophyseal joints (or facet joints), are a plane synovial joint which located between the articular facet processes of the vertebral arch. These joints are considered freely movable; the degree of possible motion varies according to the individual structural design and facet planes. Ten dried vertebrae were used for each cervical, thoracic and lumbar regions (220 vertebrae). AutoCAD program finds measurement for the surface area, the curvature, and the angle of the facet processes in each region for the vertebral column. Vernier tool used to determine the shape of the facet surface. A Finite Elements Analysis model was applied on the fourth lumbar vertebra (L4) to reveal stress pathways across the joints by using ANSYS program under different loading conditions. Results by AutoCAD, determine the facet surface area gradually increased in the cervical region and become sharper increment in the lumbar vertebrae, in contrast to the thoracic region the trend become decrement. The curvature of the facet processes show changes from region to region for the vertebral column to support the stability and shifting the load in accordance with position of the line of gravity. The angles of the articular facet processes show a gradual change of orientation by articular facet from cervical region to the thoracic region and sudden change from thoracic region to the lumbar region. Results obtained from the ANSYS program are important in understanding the boundary conditions for load analysis and the points of stress concentration which explained from the anatomical point of view and linked to muscle and ligament attachments. This model used as a computational tool to joint biomechanics and to prosthetic implant analysis.