Abstract: Objective To provide basic data of the screw channel for the clinical application of the posterior internal fixation with a steel plate for vertical sacral fractures through the anatomic measurement of the sacrum.Methods According to the requirement of the screw channel of the sacral posterior internal fixation with a steel plate, the inserting sites were determined on 20 cases of the selected adult sacrum specimens: point a at the in lateral side of S1 articular process, point b at the downside of S1 articular process, points c, d and e of S2, S3 and S4 along the imaginary line between point a and the top edge of S4 dorsal sacral foramina, respectively, at the midpoint of the line between adjacent dorsal sacral foraminas. The distances between inserting sites were af, bg, ch, ci, dj and ek, respectively; the lengths of inside screw channels were A1, A2, B, C, D and E, respectively; the lengths of outside screw channels were F, G, H, I, J and K, respectively and the angles of outside screw channels were Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴand Ⅵ, respectively. Results A1, A2 and B values were (31.70±3.54)mm, (35.59±4.50)mm and (27.83±3.80)mm, respectively; F, G, H, I and J values were (43.68±5.11)mm, (30.10±4.00)mm, (27.66±3.33)mm, (23.51±3.26)mm and (18.72±4.18)mm,

Key words: Vertical sacral fracture, Posterior internal fixation with steel plate, Screw placement, Applied anatomy, Human