OBJECTIVECervical vertebra semidislocation was one of major pathological aspects of cervical spondylosis, and it was also the target of manipulation to treat cervical spondylosis. The aim of this study was to combine the technology of three dimensional finite element analysis to investigate the method to construct the cervical vertebra semidislocation model.

METHODSA cervical spondylosis patient (male, 28 years old,176 cm tall, weight 69 kg) was randomly chosen, who was diagnosed cervical vertebra semidislocation by dynamic and static palpation and X-ray,and CT scanned from C1 to C7 by 0.75 mm slice thickness. Based on the CT data, the software was used to construct the three dimensional finite element model of cervical vertebra semidislocation (C4-C6).

RESULTSThe model showed the three dimensional changes of vertebra semidislocation clearly. C5 had a three-dimensional abnormal position, which was downward translation for 0.9 mm and clockwise rotation for 4.5 degrees around X-axis. So C5 was diagnosed as hypokinesis-type semidislocation.

CONCLUSIONThe method to construct the three dimensional finite element model of cervical vertebra semidislocation is reliable, which provide a base study to analyse the mechanism of manipulation to treat vertebra semidislocation.