Studies on lung volume. VII. Relation of size of chest to lung volume

Abstract

In 1918 Lundsgaard and Van Slyke 1 worked out the quantitative relationship between the different lung volumes and the size of the chest (so-called chest volume) in 18 normal individuals. The size of the chest was determined as the product (“chest volume”) of three dimensions, the height, depth, and width of the thorax. The ratio between the chest volume and the lung volume in the corresponding position was found to be 55 for maximum expiration, 37 for middle capacity, and 19 for maximum inspiration. We thought it would be of value to increase the number of observations. We used the technique described by Lundsgaard and Van Slyke in measuring the chest dimensions and the total capacity. Complete mixture has always been present. The residual air we determined indirectly as the difference between total capacity and vital capacity and the middle capacity was determined by rebreathing from a spirometer. 2 The material includes 27 normal subjects (18 men and 9 women). The figures for the relative lung volumes reported in a previous communication, are based on the same observations. We obtained the following average figure (Table I). It is in approximate agreement with the figures obtained by Lundsgaard and Van Slyke (Table II). The discrepancies are probably due to the fact that the middle capacity, the vital capacity, and the residual air are determined in a slightly different way. (See Lundsgaard and Van Slyke, and Lundsgaard and Schierbeck. 3 We believe that the procedure adopted in this paper is the more preferable. The mean error on each determination helps in deciding whether or not an observation in a patient may be considered pathological or not. The ratio between the “chest volume” in after maximum inspiration and maximum expiration respectively indicates the range of the thorax movement.