Abstract:

Objective　To provide anatomic data for lateral and anterior fixation of the middle and lower thoracic vertebra according to the location of costal facet.   Methods　On 40 intact specimens of the middle and lower thoracic vertebra((T4～T12), with the age from 25 to 60, the distances from anterior border of costal facet to anterior border of vertebral foramen (DCFC), from anterior border of vertebral foramen to anterior border of intervertebral foramina(DCF), from inferior border of costal facet to superior border of superior terminal plate(DIFSP) were measured respectively. CT data of 6 healthy adults were used to reconstruct and simulate screw canal fixation.  Results    The DCFC decreased gradually from the middle to lower thoracic vertebra, however, there were no obvious difference for DCF, despite of minimum value of T6, and maximum value of T4.  DIFSP gradually increased from T4 to T12.  The coordinate of the screw gradually removed to the superior of the lower thoracic vertebra, with the increased length of screw canal.   Conclusions    The location of costal facet gradually reaches the posterolateral of vertebra from middle to lower thoracic vertebra, which is a valuable reference for determining the site of screw fixation and the length of screw canal.

Key words: Middle and lower thoracic vertebra!Costal facet!Lateral-anterior fixation!Digital anatomy