Pulmonary Agenesis and Hypoplasia

In recent years the more frequent use of x-rays has revealed various congenital abnormalities of the lungs which had formerly passed undetected during life, since the clinical signs and symptoms may be minimal. An attempt is made here to elucidate the different pictures which may be seen in varying degrees of underdevelopment of the lungs. For clarity of description the following nomen-clature is based on Schneider's (1912) classification: AGENESIS of a lung, where there is complete absence of lung and bronchus. APLASIA of a lung, where there is a rudimentary bronchus and no pulmonary alveolar tissue. HYPOPLASIA of a lung or part of a lung, where the alveolar tissue is underdeveloped.