Inferiorly, the pleura reflects onto the diaphragm above the costal margin and courses around the thoracic wall following an VIII, X, XII contour (i.e., rib VIII in the midclavicular line, rib X in the midaxillary line, and vertebra TXII posteriorly).
The lungs do not completely fill the area surrounded by the pleural cavities, particularly anteriorly and inferiorly.
Costomediastinal recesses occur anteriorly, particularly on the left side in relationship to the heart bulge.