Results
From a total of 60 volunteers responding to the announcements, one was excluded due to respiratory complications. Fifty-nine asymptomatic subjects (52.5% males) were included. After assessing both sides on each subject in both maximum inspiration and expiration, we analyzed a total of 236 measurements. Table 1 provides sociodemographic and anthropometric data of the total sample, and divided by gender, respiratory moment, and side. In general, men exhibited higher age, height, weight, BMI, thorax perimeter, rhomboid depth, pleura depth, and rhomboid-to-pleura distance (all, p<0.001). No side-to-side differences were found in any feature. Differences were found between inspiration and expiration for thorax perimeter (p<0.001), rhomboid to pleura distance (p<0.001) and pleura depth (p<0.001), but rhomboid depth showed no differences (p>0.05).
Table 2 summarizes Pearson’s correlation coefficients of rhomboid and pleura depth with anthropometric features. Pleura depth was correlated with respiratory moment, age, perimeter, weight, height, BMI, and gender. Rhomboid depth was correlated with perimeter, weight, height, BMI, and gender, not age. In addition, significant correlations also existed among the anthropometric variables with no multicollinearity (except height with BMI and perimeter); therefore, height was excluded from the regression analysis.
Table 3 describes the hierarchical regression analysis conducted in this study for determining pleura depth. BMI contributed with 55.9% of the variance (p<0.001), gender contributed an additional 13.3% (p<0.001), and thorax circumference the last 0.5% of variance (p<0.05). When combined, anthropometric features explained a total of 69.7% of variance of pleura depth.
Table 4 shows the hierarchical regression analysis conducted for rhomboid major depth. BMI contributed the 42.2% of the variance (p<0.001), gender contributed an additional 8.7% (p<0.001), and thorax circumference the last 0.6% of variance (p<0.05). Therefore, the combined model explained 51.5% of variance for predicting the rhomboid depth.