MORPHOLOGICAL OBSERVATION ON THE BONY LUMBAR VERTEBRAL FORAMINA, LATERAL RECESSES AND INTER VERTEBRAL FORAMINA

One hundred and twenty dry lumbar spinal skeletons of Chinese adults were observed and measured. Statistical analysis was undertaken. The shape and size on every level of the lumbar vertebral foramina and the data of the factors influencing the vertebral canal and nerve root canals were reported, the differences in age and sex were discussed. There is a tendency that the shape of the vertebral foramina from L1 to L5 changes from oval to trefoil. The narrowing of the lateral recess or nerve root canal in lower lumbar spine is of importance. The mid-sagittal diameters of vertebral foramina tend to be smaller from L1to L3 and larger slightly from L3 to L5. Their size may be influenced by congenital or developmental factors. The lateral-sagittal diameters tend to become smaller and smaller from L1 to L5. Their size has some relation to age and spinal degeneration. The narrowing of the mid-sagittal diameter may involve the cauda equina mainly in central vertebral canal. While the narrowing of the lateral-sagittal diameter may involve the L5 and S1 spinal nerve roots participating in the sciatic nerve mainly in the lateral recesses and nerve root canals. The lumbar spinal stenosis can be classified into central, lateral and mixed types morphologically.