The Role of Articular Facets During +G_z Acceleration

Experimental evidence is presented to document the load-bearing capability of the articular facets which join the vertebrae of the spine together posteriorly. Contrary to the general opinion that these facets carry no vertical load, this paper gives qualitative as well as quantitative data to show that there exists a dual load path along the vertebral column. Extensively instrumented human cadavers were used as test subjects. Strain gages were used to provide qualitative evidence of facets load while a unique intervertebral load cell supplied quantitative information of the load-bearing role of the facets. The results of this study led to a clearer understanding of the mechanism of injury to the vertebral column during +G_z impact acceleration.