Reliability of scapular positioning measurement procedure using the palpation meter (PALM)

Observation and measurement of the static position of the scapula is important for investigating both shoulder and neck pathology. Measurement of scapular position is complex and lacks a clinically useful instrument. The objective of this study was to investigate the reliability of the Palpation Meter (PALM) for measuring scapular position when the glenohumeral joint is held in various positions.

Thirty normal subjects were recruited for a test-retest reliability study. Three raters conducted measurements on two different occasions to estimate intra- and inter-rater reliability. The scapular positions evaluated in this study were: (1) the horizontal distance between the scapula and the spine in the scapular resting position and during elevation of the arm in the scapular plane; and (2) the vertical distance between C(7) and the acromion (C(7)-A). Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and Bland and Altman limits of agreement were calculated.

Reliability values for measurements of the horizontal distance between the scapula and the spine were generally good for both intra-rater (ICC 0.81 to 0.89; SEM 0.56 to 1.17cm) and inter-rater (ICC 0.67 to 0.89; SEM 0.59 to 0.98cm) evaluation. Reliability values of measurement of depression of the acromion were also good for both intra-rater (ICC 0.72 to 0.78; SEM 0.66 to 0.79) and inter-rater (ICC 0.76; SEM 0.64) evaluation. No systematic bias was observed with Bland and Altman analysis.

The PALM is a reliable tool for the measurement of scapular positioning in a healthy sample. Future studies should be conducted to further investigate the clinometric properties of the PALM in patient populations before its clinical usefulness for measuring scapular position can be established.