Fig. 4: Development of "sagittal translation" tr
(data depicted accordingly to Fig. 3).
1: cranial adjacent vertebra (upper vertebra of the cranial adjacent segment);
2: topmost fusion vertebra;
3: second fusion vertebra;
4: caudal adjacent vertebra (upper vertebra of the caudal adjacent segment).
Note the lack of anterior displacement of 1 and the nearly constant sagittal displacement of 1 and 4. Slight reduction of anterior displacement in the fusion segments is temporary.