| Objective: To hunt for a bony anatomical landmark with rare variant and closely linked with the pedicle, in order to accurately determine the entry point of the pedicle screw, and to define the relationship between the crisra of transverse process and the transverse axis of the pedicle. To carry out a preliminary anatomy study with a view to provide a basis for the clinical application of the thoracic pedicle screws.Methods:Material: 1) To extract 100 (200 sides)scattered dry specimens of normal adult thoracic vertebrae. 2) A vernier caliper.Steps: To observe the occurrence rate of crisra of transverse process in thoracic vertebra, and to measure the following structures by vernier caliper. 1) The vertical distance between the tiptop of superior articular process and the ipsilateral crisra of transverse process in thoracic vertebra. 2) The vertical distance between the tiptop of superior articular process and the ipsilateral upper edge of the pedicle in thoracic vertebra. 3) The sagittal diameter of ipsilateral pedicle. 4) To acquire the vertical distance between the upper edge of the pedicle and ipsilateral crisra of transverse process, calculated the ratio of this distance and the sagittal diameter of ipsilateral pedicle, then the Paired t test was undertaken.Results: 1) The mean of left: 0.487±0.0475; The mean of right : 0.484±0.0436, there have no statistical significance between both sides(P=0.705),. 2) Population mean: 0.486±0.455. 3) There have statistical significance between the mean of Left and 0.50(T=2.757, P=0.007), but there have statistical significance between the Right and 0.5(T=3.592, P=0.001). 4) The Left (T=0.654, P=0.517) and Right (T=1.3, P=0.197) compared with 0.49, the differences all have no statistical significance. 5) Compared with 0.48, the Left (T=1.455, P=0.149) group and Right (T=0.993, P=0.323) group all have no statistical significance, too.Conclusion: There was a high occurrence rate of crisra of transverse process in thoracic vertebra, and the variation was rare,it was perfect matched with the central axis of pedicle of thoracic vertebral arch. Accordingly, this anatomic structure was significantly for definite the entry point in the procedure of pedicle screw placement, and this subject deserves intensive study for us in future. |
