Topography of pleural surface pressure after pneumo- or hydrothorax

of pleural swjace fwessure after pneumo- OY hydrothorax. J. Appl. Physiol. 32(3) : 296403. 1972.-Pleural surface pressure was studied before and after pneumo- or hydrothorax to determine whether the changes of pressure produced in the regions facing them were shared by the regions where the lung was still in contact with the rib cage. Hydrothorax was produced in supine cats and rabbits, pneumothorax in supine rabbits and dogs and head-up dogs. Pleural surface pressure in the regions where the lung still con-tacted the rib cage did not change appreciably after small- and medium size hydro- or pneumothoraxes in spite of the changes occurring in the regions facing them. In supine rabbits the pres-sure in a small pneumothorax made beneath the xiphisternal joint was a little higher than the approximate ayerage pleural surface pressure occurring normally on the corresponding costal side, whereas in supine dogs it was lower. This peculiar finding