Humeral Head Morphometry Can Predict the Presence of Subacromial Spurs: Measurements of Dried Bones from Human Shoulder Girdles.

To clarify the relationship between the morphological characteristics of the bones of the shoulder girdle and the presence of subacromial spurs (SS). The bones of 36 cadaveric shoulder girdles were measured. After dividing the bone specimens into SS present and absent groups, various bone parameters between the two groups were statistically compared. Logistic regression analysis was conducted to assess the significance of each parameter as a predictor of SS formation. A receiver operating characteristic curve analysis was used to determine the cut-off point and to assess the sensitivity and specificity of the parameters showing significant differences. SS were found in 16 scapulae. The values for five parameters of the examined shoulder girdles were significantly different between the two groups. The presence of SS depended on the humeral head ratio, which was calculated by dividing the length of the greater tubercle of the humerus by the length of the lesser tubercle. A cut-off value of 1.97 was suitable for discriminating between the presence and absence of SS (sensitivity, 75%; specificity, 80%). The presence of SS is related to several morphological characteristics of the shoulder girdle and, the presence of SS can be predicted using humeral head morphometry.