Objective    To explore the morphological characteristics of pressure bone trabeculae of femoral head and neck, posteromedial bone cortex of femoral neck and femoral calcar, in order to provide morphological basis for the pathogenesis of femoral neck fracture.    Methods    A total of 102 femur specimens were collected. X-ray films of the upper end of the femur were taken at anteroposterior, lateral, 45° internal oblique and 45° external oblique, respectively. The position relationship of pressure bone trabeculae, calcar and posteromedial bone cortex of femoral neck were observed. Sixty cases of femoral specimens among them, there were 34 specimens in normal group and 26 cases in osteoporosis group. The head and neck of femur were scanned and reconstructed by CT. The morphological differences of pressure bone trabeculae and calcar were compared between the two groups. Six femur specimens were dissected along the vertical, coronal and sagittal surfaces of the femoral neck to observe the morphological characteristics of pressure bone trabeculae, posteromedial cortex of femoral neck and femoral calcar. The data were analyzed by Graphpad Prismv5.0 software.   Results   The pressure bone trabeculae of head and neck of femur concentrated inward and backward, and it stopped at posteromedial bone cortex of femoral neck and continued with the calcar. The greater intertrochanteric bone trabeculae of femoral calcar emerged outward from femoral calcar and thinned in osteoporosis group. The pressure bone trabeculae was cross-connected with femoral calcar, with an angle of (82.96±2.91)° in normal group and (116.40±3.23)° in osteoporosis group, and the difference was statistically significant. There was statistical difference  in the calcar angle on cross-section between two groups [(17.52±0.71)° in normal group and (13.09±0.90)° in osteoporosis group].    Conclusions    The pressure bone trabeculae of femoral head and neck, as well as the upper end of femoral calcar, are attached to the posteromedial bone cortex of femoral neck. The posteromedial cortex of femur neck and femoral calcar jointly bear compressive stress, and the migration site is the pressure transmission hubs. When osteoporosis occurs, femoral calcar becomes smaller, and the cortical bone at the junction between femoral calcar and pressure bone trabeculae is weaker. These may be one of the mechanisms of osteoporotic head-and-neck femoral neck fracture.