The present study investigates how loading of the shoulder effect the formation of the trabeculae in the subarticular region of the gleno-humeral joint. Bone morphology was determined from scapular cadaveric specimens and finite element (FE) analysis was employed to analyse principal stress trajectories. Boundary conditions corresponded to five functional activities were considered. The results show deviations of the computed trajectories from actual trabecular lines obtained from the bone specimens ranged on average from 10% to 17%. Each activity produced different regional deviation corresponding to the specific loading condition. This study concludes that certain loading conditions are more significant in explaining the formation of the trabecular architecture. The results also suggest that due to the extra sensitivity of the front and the rear aspects of the "lateral region" to the loading conditions, these regions may be more indicative in reflecting shoulder injuries.

Researchers have tried to assess the morphological and mechanical characteristics of bone using various methods with a limited success (Mow and Hayes, 1997, and Cowin, 2001). This may be due to the complexity for documentation and characterization of architecture by the anisotropic and nonhomogeneous characteristic of the bone. The bones of the shoulder joint complex are particularly deprived of information on their mechanical and morphological properties. Very little is known for example on the mechanics and morphology of the glenoid of the shoulder. The present work presents an attempt to identify a proper method for the measurement and characterization of the morphology and mechanics of bone, particularly in the glenoid. Our results show that trabecular lines are directed at 82.15° ± 7.98° relative to the glenoid articular surface, young’s modulus obtained from CT scan was 230 ± 8 MP, and the elastic tensors obtained from cadaver were 326 ± 78 MPa for E2222, 144 ± 22 MPa for E1111=E3333, 49 ± 7 MPa for E3311, 59 ± 9 MPa for E1122=E2233, 51 ± 8 MPa for E1313, and 70 ± 10 MPa for E1212=E2323. These results were consistent with Wolf’s Law and were in agreement with results reported in literatures (Anglin et al., 1999, Frich et al., 1998, and Mansat et al., 1998).