Comparison of skin-to-bone distance in the interscapular region when measured in the prone position and in the seated position in a therapy massage chair.

[Purpose] To investigate whether the skin-to-bone distance at specific points in the interscapular region differs when measured in the prone and seated positions. [Participants and Methods] Eighteen healthy males (age, 22-63 years; height, 161.5-181.5 cm) were recruited. The skin-to-bone distance at Points A (fifth rib, near acupoint BL43) and B (eighth rib, near acupoint BL46) was measured using ultrasonography in the prone and seated positions. In the prone position, the participants laid on a bed with their shoulders abducted at 90°, and in the seated position, a commercial massage chair was used. [Results] The mean distance at Point A in the prone position was 2.7 ± 0.4 cm (range, 1.9-3.4 cm). The mean distance at Point B was lower than that at Point A in the prone and seated positions, with no significant difference in the distance between the two positions. [Conclusions] The skin-to-bone distance in the interscapular region did not differ significantly when measured in the seated and prone positions. Tissue components in some anatomical areas change with posture, whereas others do not. Further studies on posture-induced changes to tissue components are necessary to improve understanding of these variations.