The shape of the chest of the tuberculous patient and that of the normal is so strikingly different that a study of the various diameters proves very interesting.
It is still a common belief that the flat chest or, rather, the one with a low thoracic index is apparently more prone to tuberculosis than the deep chest with a greater thoracic index. By the thoracic index is meant the ratio of the anteroposterior measurement to the transverse.
In 1828, Chomel1 stated that the normal chest was flatter than the tuberculous. Hutchinson2 in 1897 and again in 19033 showed that the tuberculous chest was absolutely narrower, deeper and more round than the normal; that it was a primitive, undeveloped thorax, one approximating that of the quadruped type. In his study of comparative anatomy he showed that the higher the form of mammal the greater was the transverse diameter
WEISMAN SA. CONTOUR OF NORMAL AND TUBERCULOUS CHESTS. JAMA. 1927;89(4):281–284. doi:10.1001/jama.1927.02690040021008