Purpose: We measured dorsal and ventral thoracic 12 vertebral (T12V) body heights as a way to predict lumbar vertebral fracture (LVF) in postmenopausal women. MRI of dorsal and ventral T12V body heights has not yet been used to investigate their association with LVF. We hypothesized that the dorsal and ventral T12V body height are important morphologic parameters in the prediction of LVF. Patients and methods: In total, 80 osteoporotic patients with LVF (LVF group) and 80 osteoporotic patients without LVF (control group) were examined by MRI at the lumbothoracic level. Sagittal T2-weighted MRI images in the T12 level were obtained from all subjects. We analyzed both the dorsal and ventral T12V body height. The difference in dorsal and ventral body heights of the control and LVF patients was calculated at the T12V level. Results: The average dorsal T12V body height was 21.25±1.64 mm in the control group and 20.11±1.49 mm in the LVF group. The average ventral T12V body heights were 19.51±1.54 mm and 17.62±1.95 mm, respectively. The LVF group had significantly lower dorsal and ventral T12V body heights (both P,0.001). ROC curve analysis showed the best cutoff value for dorsal T12V body height value of 20.74 mm, with 62.5% sensitivity and 60.0% specificity. The best cutoff point of ventral T12V body height was 18.76 mm, with 68.8% sensitivity and 67.5% specificity. Conclusion: This study confirmed the association between dorsal and ventral T12V body height and occurrence of LVF in postmenopausal women with osteoporosis. Dorsal and ventral T12V body height were both significantly associated with LVF, with ventral T12V body height being a more sensitive measurement parameter. Thus, to predict risk of LVF in patients, the treating physician should carefully inspect the ventral T12V body height.