Methods ： fifty paired embalmed cadaveric humeri ( twenty - five pairs : fourteen from male donors and eleven from female donors ) were scanned in medial - lateral ( ml ) and anterior - posterior ( ap ) position according to the humeral retroversion by ct . images of the humeri in the transverse planes at the lowest border of neck ( lbn ) , 20mm and 40mm distal of lbn ( lbn - 20 、 lbn - 40 ) , isthmus , head - neck anterior - posterior ( hn - ap ) were obtained . sixty - one extracortical and intracortical parameters were measured exactly by image analytic computer software that included offset , head position , head - shaft angle , head to tuberosity height ( ht ) , head thickness , curvature radius , articular surface arc ( sa ) , neck diameter , isthmus position , proximal and distal border of isthmus , maximum coronal and sagittal diameter of medullary canal and thickness of cortical bone in four planes , including lbn , lbn - 20 , lbn - 40 and isthmus 方法： 50根成对防腐肱骨(男14对，女11对)按肱骨头扭转角置于冠状位和矢状位，行肱骨全长，头颈矢状面，解剖颈下缘及其下20mm 、 40mm ，髓腔狭窄部四平面ct扫描，由ct软件测量冠、矢状位髓腔内外参数共61项，包括头心?干轴距，头位置，头干角，头?结节高度差，头厚度，头半径，关节面张角，解剖颈直径，髓腔狭窄部位置，解剖颈下缘及其下20mm 、 40mm和狭窄部四个平面髓腔的最大冠、矢状径，皮质骨厚度等。
