[Anatomic observation and clinical significance of vertebral pedicle]

To be aware of the security in fixing the spine through posterior approach with instrumentation, a study of the regional anatomy of the pedicle was done by measuring various parameters in 51 thoraco-lumbar (T-9 to L-3) specimens, including the thickness, height, and length of pedicle, the angles made by line of the pedicle axis with both the sagittal and longitudinal lines of the same vertebral body, and the distance between pedicles of each vertebra. The space between spinal cord and pedicles on cross section of 35 cadaveral specimens was also measured. For purpose of comparison to find out the anatomical significance for clinical application, measurement of corresponding parameters on CT scan films of 50 cases were carried out. Taking into account of all these parameters, findings and some clinical experience, detailed discussion about operative indications, procedures of internal fixation and the inserting point along with the direction of drilling screws in were made.