Reliability of palpation of humeral head position in asymptomatic shoulders

The purpose of this study was to determine if, within a normal population: (1) palpation of the humeral head, relative to the acromion, in three static positions, was a reliable technique (2) there was a difference in humeral head position between the dominant and non-dominant shoulders in the three positions (3) there was a difference in humeral head position relative to the acromion between the arm at side (AS), the 90 ° abduction/external rotation (AER) and 90 ° abduction/internal rotation (AIR) positions. This test-retest study recorded palpation landmarks using a standardized protocol. Intra-tester reliability was above 0.8 for both AS and AER and all other ICCs were below 0.6. There was no systematic difference between dominant and non-dominant sides in any of the three positions (AS P=0.408, AER P=0.448, AIR P=0.233). There was a significant difference in measurements between each position (P<0.001). It can be concluded that, palpation of humeral head position in relation to the acromion is a reliable technique in the AS position. These normative data provide a baseline that can be used for future comparison if differences are found to exist in subgroups with pathological shoulder conditions where larger glenohumeral translations are thought to exist.