Anatomical characteristics of the scapula predisposing to subcoracoid impingement syndrome.

No significant correlations were found among the anatomical parameters analyzed, which were also independent of the dunensions of the scapulae. Three configurations of the coracoglenoid space were identified. In Type I (45% of the scapulae) the space had a "round bracket" configuration, whereas in Type II and III it had the shape of a "square bracket" (34%) and a "fish hook" (21%), respectively. Coracoglenoid distance displayed the lowest values in the scapulae with a Type I configuration. Morphometric characteristics which might predispose to subcoracoid impingement (obtained considering the mean value plus or minus the standard deviation of evcr\ variable) were found in 4% of scapulae. A total of 27 scapulae, nine for each type of configuration, were submitted to CT. Scapulae with a Type I configuration were found to have low values of the coracoglenoid angle and coracoid overlap, which are known to be associated with a short coracohumeral distance. Conclusions. Type I configuration implies a short coracohumeral distance. Measurements of the coracoglenoid space on standard CT scans, which are much easier than measurements of the coracoglenoid angle and coracoid overlap, may lead to identify athletes with a narrow coracohumeral space. This condition, however, is not sufficient for diagnosing idiopathic subcoracoid impingement. In fact, T\pe I configuration was associated with the other anatomical characteristics predisposing to abnormal narrowing of the coracohumeral space m only 4% of scapulae, a much higher figure than the prevalence of clinical syndrome appears to be. It is thus conceivable that constitutional anomalies or pathological conditions of the regional soft tissue or bony structures should also be present for the clinical syndrome to develop.