OBJECTIVETo measure the diameter of T4 pedicle-rib compomers in normal human spines and discuss the importance of related dates.

METHODST4 computerized tomography (CT) images,including two-dimensional,three-dimensional reconstruction, of 12 random adult patients were harvested. There were 7 males and 5 females with a mean age of 23 years (ranged, 19 to 28 years). The patients were divided into groups by self control,which means the diameter of pedicle compared with that of pedicle-rib unit in the same side of each T4. The facility was GE light speed 16. Measurement of the body specimens from T3 to T5 . The parameter included the width of pedicle-rib unit compared with pedicle,the longitudinal diameter of pedicle-rib unit compared with pedicle, especially for the pedicle-rib overlap.

RESULTSThe relationship of T4 pedicle and rib were not on the same level but overlapping. The width of pedicle-rib unit was significantly larger than that of pedicle (P<0.05). The longitudinal diameters of pedicle-rib unit or pedicle were significantly larger than those of pedicle-rib overlap (P<0.05); while there was no significantly difference between the pedicle-rib unit and pedicle (P>0.05).

CONCLUSIONThe overlapping relationship of T4 pedicle and rib is partly but not whole, which means the longitudinal diameter of T4 pedicle-rib overlap should not be considered as the same of unit or pedicle.