The area of glenoid asymmetry identified as important contributor to shoulder strength during pushing and pulling in the coronal plane.

The geometrical dimensions of the bones that make up the glenohumeral joint could be a key factor in strength predictability. Understanding the mechanical influence of these dimensions (individually or in combination) on shoulder strength could help explain the mechanism of musculoskeletal disorders. The following study shows how a recently discovered geometric parameter, the area of glenoid asymmetry (AGA), is a good indicator of shoulder strength. A comprehensive study was conducted to test whether glenohumeral geometry, as measured through MRI scans, is correlated with upper arm strength. The isometric shoulder strength of 12 subjects during one-handed arm abduction and adduction in the coronal plane, in a range from 5 to 30 degrees , was correlated with the geometries of their glenoid fossae. All subjects were stronger during adduction than abduction for all arm positions. The results revealed a high correlation in the coronal plane between the AGA and mean maximum force and mean maximum moment when an arm was abducted and adducted in a range from 5 degrees to 30 degrees (0.80, p </or= 0.01 and 0.69, p <or= 0.05, respectively during abduction and 0.61, p <or= 0.04 and 0.61, p <or= 0.04, respectively during adduction). This investigation revealed the repercussion of individual glenoid geometry on the maximum acceptable load applied to the hand during arm abduction and adduction in a coronal plane.