Anatomic Study Of The Pedicle Screw Placement Technique On Sacrum 2

Objective:To explore the relations between the pedicle of sacrum 2 and which ,sacral rear foramina and lateral sacrum process. And set up a technique of sacrum 2 pedicle screw placement with sacral rear foramina and lateral sacrum process as anatomiclandmark. Methord:30 sacrum bones specimens were used, cut the sacrum from the first and the second vertebral vestige ,from the second and the third vertebral vestige, and parallel to plan of sacrum bottom. To observe pedicle shape and the adjacent relation. To cut the sacrum from the mid point of the first and the second sacral rear foramen, parallel to the bottom of sacrum.To speculate the relation between pedicle and lateral process of sacrum, and measure some angles and lengths.To observe 10 cadavers's sacral structure.Result:the pedi cle of sacrum 2 is fan-shaped, run from rear lateral to front medial. The midline of pedicle is rightly through the midpoint of the first and the second rear foramina of sacrum. We can place the pedicle of sacrum 2 in the point of intersection that sacral lateral process and the line through the first and the second foramina.The length of pedicle si 27.53mm---35.46mm,the angle is 3 0.23°----4 5.73°.There is a safe region in front of the sacr u m.C onclu sions:There is steady anatomic relation between sacrum 2 pedicle and which rear foramina of sacrum and lateral process of sacrum. They could be as a convenient key anatomic landmark to determine the location of sacrum 2 pedicle and the position of sacrum 2 pedicle screw entry point.The location of the screw just in the safe region.