The right inferior lung margin: anatomy and clinical implication.

Medical students and clinicians have, for generations, based their knowledge and application of anatomy on the study of cadavers which have been fixed in formalin. Assumptions are made that structures maintain the same relationship in the living as in the dead. Such a belief is untrue in respect of the inferior extent of the lung and pleura into the posterior diaphragmatic sulcus. This study of the plain abdominal radiographs of 100 adult patients demonstrates a clear difference between the classical anatomical teaching, which describes a potential space containing only pleura in the recess, and our finding that in the living patient lung extends deep into the sulcus. In 80% of patients, lung is seen to lie at or below the level of the 12th rib, while in 18% lung reaches the level of the body of L1. Medical students should be made aware of this and clinicians should approach the liver, adrenal gland and kidney posteriorly with caution in order to avoid traversing lung and pleura.