Accuracy of Anterior Superior Iliac Spine Symmetry Assessment by Routine Structural Examination

Assessment of the anterior superior iliac spine (ASIS) is a key component in generating the pelvic diagnosis of somatic dysfunction, but studies have shown poor reliability between examiners.

To assess the influence of homogeneous training, years of experience, and eye dominance on the percentage of correctness, sensitivity, and specificity of ASIS evaluation.

Osteopathic physicians, predoctoral teaching fellows, and first- and second-year osteopathic medical students from a single teaching institute assessed 3 plastic pelvic models with ASIS anatomic landmarks set at different levels: even and 5- and 10-mm descrepancies. Dominant and nondominant eyes were used independently to assess ASIS levels.

A total of 147 examiners (participants) participated in this study (66 first-year and 61 second-year medical students, 15 fellows, and 5 osteopathic physicians). The overall percentages of correct results were 31.0% (even levels), 82.8% (5-mm discrepancy), and 91.7% (10-mm discrepancy). Differences by level of training were statistically significant only for the 5-mm ASIS discrepancy, where participants with more experience performed better. The overall sensitivity was 82.8% (5-mm discrepancy) and 91.7% (10-mm discrepancy), and the specificity was 31.0%. No statistically significant differences were found in the percentage of correct results by eye dominance.

Assessment of ASIS is sensitive but not specific at discrepancies of 5 mm or greater. Length of experience positively influences the percentage of correct results, and eye dominance does not significantly change this outcome. This form of assessment can be used to screen for ASIS asymmetry.