Effect of scoliosis on growth of alveoli and pulmonary arteries and on right ventricle.

During childhood the lung not only grows in size but alveoli and arteries multiply and the pattern of muscularity of the arteries changes. A quantitative study is here reported on 4 cases of scoliosis. The limitation and distortion of space available affect lung growth. In scoliosis, alveoli are too few in number, often emphysematous, and may even atrophy, the changes being irregularly distributed throughout a lobe or lung. Generally, the size of the large pulmonary arteries is appropriate to the lobar volume and hence small for the age of the child: arterial muscle hypertrophy and abnormal extension to the periphery were seen only in 2 of the 4 cases in which there was right ventricular hypertrophy. In these, hypoxaemia had been present for some time before death and this, not hypoplasia, seemed responsible for the muscle hypertrophy. In 2 cases where scoliosis was associated with a mesodermal dysplasia, there was an excessive number of intra-acinar arteries.