Facet Orientation and Spinal Canal Configuration

The facet orientation was determined by A-P X-ray films of 20 dried specimens of lumbar spine, and the facet angle and spinal canal configuration were directly measured useing the same specimens.Difference between the sagittal and coronal plane facet on X-ray film was clearly identified in direct measurement of facet angle of dried vertebra. The critical angle was 50 degree. But there was almost no difference of facet angle between the oblique and sagittal plane facet.The sagittal facet plays an important role to spinal canal configuration in the lower lumbar spine. But determination of spinal canal configuration only by facet orientation useing X-ray film may lead us to misunderstanding. So our method of measurement, previously reported, is reasonable to determine the spinal canal configuration.