Abstract: Objective The morphological data of the second thoracic vertebra and the third lumbar vertebra were measured by computerized tomography （CT）. The sex differences were analyzed and the discrimination equation was obtained. Methods The data of 274 adults （203 cases from experimental group and 69 cases from validation group） from central China were collected. Four linear data （maximum transverse length of vertebral body, maximum longitudinal length of vertebral body, maximum transverse length of vertebral foramen, maximum longitudinal length of vertebral foramen）, one angle data （angle between spinous processes） and two area（vertebral foramen area, total cross-sectional area of vertebral body） data of the second thoracic vertebra and the third lumbar vertebra were collected, respectively. Then three ratios［maximum transverse length/ maximum longitudinal length of vertebral body, maximum transverse length/ maximum longitudinal length of vertebral foramen, vertebral foramen area/ （total cross-sectional area of vertebral body-vertebral foramen area）］ and one angle （angle between spinous processes） were obtained. The discriminant equation was established for sexual discriminant analysis. Results The morphology of the second thoracic vertebra and the third lumbar vertebra was related with gender. Four single index discriminant formulae and eleven multi- index discriminant formulae were established. The 69 validation group samples were substituted into the formula for testing, and the maximum discriminant accuracy rate of the single-index discriminant formula was 75%. The maximum discriminant accuracy rate of multi-index discriminant formula was 83%. Conclusion It is feasible to conduct individual sex analysis by the morphological indexes of second thoracic vertebra and the third lumbar vertebra. The indexes have important application values in practice.

Key words: forensic anthropology, thoracic vertebra, lumbar vertebra, sex estimation, computerized tomography