Background and aim: The lateral scapular slide test (LSST) is used to determine scapular position and scapular asymmetry with the arm abducted 0, 45, and 90 degrees in the coronal plane. This test was introduced by Kibler. Assessment of scapular position is based on the derived difference measurement of bilateral scapular distances and the distance of inferior angle of scapula to spinous process of T7 vertebra. The purpose of this study was to assess the reliability of measurements (intra rater, inter rater, sensitivity and specificity) of LSST in assessment of scapular asymmetry and scapular dysfunction in patients with shoulder impairments.

Materials and Methods: Subjects:  Fifty-seven subjects participated in this cross sectional study.

Twenty seven subjects in shoulder impairment group (X=47.66, SD=11.64) and thirty subjects in normal group(X=33.53, SD=11.72). Three examiners measured the distance of inferior angle of scapula to spinous process of T7 vertebra at two sides in three different positions by a caliper verneer (accuracy: 0.01 mm). Position 1 involves of the shoulder in glenohumeral joint neutral. In position 2, the humerus is placed in a position of medial rotation with 45 degrees of shoulder abduction. In position 3, the upper extremity is placed in a position of maximal medial rotation with 90 degrees of shoulder abduction. The data were analyzed with SPSS (version: 11.5). ICCs and SEMs were calculated.

Results: The ICCs for intra-rater reliability were 0.87 to 0.97 for subjects without and with shoulder impairments and 0.63 to 0.79 for inter-rater reliability in subjects with shoulder pathology (involved side). The SEMs ranged from 0.57 to 0.86 cm for intra-rater reliability and from 0.79 to 1.20 cm for inter-rater reliability. Sensitivity of the test was high(80% to 100%) but specificity  was low (4% to 26%).

Conclusion : The lateral scapular slide test has high sensitivity and good to high level of intra rater reliability at three different test positions. The test showed low specificity and poor to fair inter rater reliability at three different test positions particularly at position 3.