ABSTRACT
Objective To observe foe microstructure of calcar femorale in young and old people andto investigate its clinical significance. Methods Twelve fresh cadaveric proximal femurs harvested from sixyoung(18~30 years) and six old (over 60 years) adults were used in this study. At first, CT scanning of allproximal femurs were taken. Secondly, the cross section of all calcar femorale were X - rayed and observedunder light microscope and scanning electron microscope. Results The calcar femorale can be divided intothree regions on the cross section. The structure of the medial region is conical bone which unites with medialcortex, and it mainly enhances the strength of the femoral neck. Its middle region is spongy conical bone andits lateral region has become trabecular bone. These two regions can transfer the compressive load that comefrom femoral head to the medial femoral cortex below the lesser trochanter, so they can disperse the load offemoral neck. Severe resorption can occur in the calcar femorale in old people, especially in the lateral region.Conclusion The destruction of three dimensional microstructure and ultra-microstructure of calcar femoralecan result in the decline of its mechanical competence and its ability of load transmission.