Carpal bone anatomy measured by computer analysis of three-dimensional reconstructions of computed tomography images

Using quantitative analysis of three-dimensional reconstructions of computed tomography scan data, a normative database of carpal bone morphology was built. Thirty-five wrists were imaged in a computed tomography scanner. Each slice was processed to determine the bone edges and assembled as a three-dimensional model by stacking. Quantitative measurements of volume, surface area, maximum length, and intercarpal distances were then assessed. A reliable three-dimensional carpal height ratio was calculated by dividing the carpal height (minimum distance between the fourth metacarpal and the radius) by the capitate maximum length. For volume, maximum length, and surface area, the order for the eight carpal bones with respect to size (in descending order) were: capitate, hamate, scaphoid, trapezium, lunate, trapezoid, triquetrum, and pisiform. Male wrists were significantly larger than female wrists. There were no significant differences in the relative dimensions between left and right wrists, or between left and right wrists of matched pairs. This technology offers automated analysis of three-dimensional geometric carpal information and the opportunity to obtain a body of information about normal and abnormal morphology as well as spatial relationships between carpal bones.