作者单位:University of Cologne, Department of Anatomy II, Joseph-Stelzmann Str. 9, D-50931 Cologne, Germany[1]University of Cologne, Children's Hospital, Joseph-Stelzmann Str. 9, D-50924 Cologne, Germany[2]Heinrich Heine University Hospital Düsseldorf, Department of Trauma and Hand Surgery, Moorenstr. 5[3]