Fig. 2From: Traditional and cortical trajectory screws of static and dynamic lumbar fixation- a finite element studyFour diagrams to illustrate the trajectory of screws from top and side views. TT static fixation(a). TT dynamic fixation(b). CBT static fixation(c). CBT dynamic fixation(d). The definitions of the Line AB and the Points A, and B are described in the contentBack to article page