ObjectiveTo provide geometric morphometric parameters for anatomical plate design by measuring the geometry of the 3rd to 9th ribs of adults using X-ray computed tomography (CT). MethodsTwenty patients receiving chest CT scan in Hebei Province General Hospital from May to July of 2012 were recruited in this study. There were 10 Han males and 10 Han females with their height of 167-180 (173±8) cm and age of 16-58 (37±18) years. None of the patients had thoracic trauma history or other disease which might influence the shape or density of ribs. After general chest CT scan, three-dimensional images of thoracic bones were constructed. The geometric shape of the ribs was analyzed and measured. ResultsThe ribs were divided into 3 sections as followed, from rib head to-37.5% of rib (section 1), 25%-75% (section 2), and 50%-100% (section 3). The maximum curvature of general curved ribs on long axis occurred in section 1 of the ribs. The third rib had the largest curvature (20.24±2.86/m). Section 2 of the 8th rib had the smallest curvature (6.14±0.96/m). The curvature of section 2 of 7th to 9th ribs was smaller than that of other 2 sections. The smallest curvature appeared in section 3 of 3rd to 6th ribs. Each rib had a retroversion angle along its longitudinal axis, and its numerical value was 30-50 degrees. The rib unrolled angle decreased firstly and then increased gradually. The cross-sectional area of marrow cavity ranged from 27.59 mm2 at the rear to 55.91 mm2 in the front. ConclusionMulti-slice spiral CT three-dimensional reconstruction of ribs can accurately measure the morphological characteristics of ribs, and provide a practical method for designing internal rib fixation plates.