APPLICATIVE ANATOMY FOR LUMBAR FORAMINAL AND EXTRAFORMINAL REGION

Objective:To have a clear understanding of specific osseous features of lumbar foraminal and extraforaminal region. Methods:Morphometric studies of intact osseous specimens of the sacrolumbar vertebrae were made on 32 cadavers of Chinese origin with direct measurement.Results:From L 1 to L 5,measurements show that the width of pedicle of vertebral arch, the distances from the lateral margin of the pars interarticularis and the inferior articular process to the midst sagittal plane become progressively wider. From L 1 to S 1, measurements show that the distances from the superior articular process to the midst sagittal plane become progressively wider. It also show that the distances from the inferior border of the origin of the L 4 and L 5 transverse processes are lower than others and that L 4/L 5 and L 5/S 1 facet joints are higher than others.Conclusion:The operative window of L 1/L 2 to L 5/S 1 becomes progressively smaller and moves to lateral further and especially L 4/L 5 and L 5/S 1.