The purpose of this study was to characterize differences between normal and osteoarthritic shoulders in terms of the orientation of the glenoid in a vertical and transverse plane (glenoid tilt), the rotation of the humerus about a longitudinal axis (humeral torsion), and the ratio of the maximum width of the glenoid to that of the humerus (glenohumeral index). Eighty-two matched right humeri and scapula from an African cadaveric population were graded on the basis of arthritic changes as Grade 0 (none), Grade I (osteophytes), Grade II (cysts or erosions), or Grade III (burnishing or eburnation) and physically measured. A coordinate axis system was used to determine glenoid tilt and humeral torsion. Arthritic shoulders had a larger glenoid transverse width (21.4 ± 2.1 mm) than normal shoulders (20.1 ±2.0mm). Horizontal gelnoid tilt was more anteverted in arthritic shoulders (8.0 ± 5.8 degrees) than in normal shoulders (3.7 ± 7.7 degrees) as well. Transverse glenohumeral index varied significantly between the graded arthritic groups of both the humerus and the glenoid while humeral torsion and vertical glenoid tilt differed between arthritic groupings of the glenoid and humerus respectively. From this study it is possible to conclude that horizontal glenoid tilt, transverse glenoid width, and transverse glenohumeral index play a role in osteoarthritis both of the humerus and of the glenoid. Vertical glenoid tilt has more specific implications in arthritis of the humerus and humeral torsion plays a role most significantly in arthritis of the glenoid.