With the increasingly frequent use of roentgen rays in medical and surgical diagnosis, the incidence of diaphragmatic hernias is now known to be considerably higher than was believed two or three decades ago. This increase in incidence is due undoubtedly to the relatively high frequency with which esophageal hiatal hernias are found in routine gastro-intestinal examinations. These account for the overwhelming majority of all diaphragmatic hernias. Leaving the congenitally short esophagus and thoracic stomach out of consideration, for these are not really hernias, hiatal hernia is always acquired. It is most often found in the middle-aged male, especially in the obese, and usually involves only a relatively small portion of the fundus of the stomach. The non-hiatal hernias, on the other hand, often involve a large portion of the abdominal viscera. Of these, some are congenital and occur through developmentally weak spots of the diaphragm, the foramen of Bochdalek or of Morgagni, or as a result of congenital absence of a portion of the leaf. Of more common occurrence is the acquired hernia which can be definitely traced to actual trauma. In spite of the fairly large volume of literature on this general subject, comparatively little attention has been paid until recently to post-traumatic hernia. Jenkinson (1), reviewing some 25 cases of hernia in 1925, “failed to find any instance where trauma played an important part in the etiology.” He believed that congenital weakness was present in every case and trauma was simply the precipitating factor. On the other hand, Harrington and Kirklin in 1938 (2), and Harrington in 1940 and again in 1943 (3, 4) emphasized the great clinical and surgical importance of trauma as an etiologic factor. It is probable that while many of the congenital hernias are present only as potential hernias and are actually brought about by trauma, a large number of the non-hiatal diaphragmatic hernias are directly attributable to the effect of injury, specifically laceration of the diaphragm. The non-hiatal diaphragmatic hernias are practically always found on the left. Their infrequent occurrence on the right, as has often been pointed out, is probably due to the protection afforded by the liver. The congenital variety is often enclosed in a sac of pleura and peritoneum. The purely traumatic type has no sac and the abdominal viscera are in direct contact with the lungs. Both varieties often involve a large portion of the gastro-intestinal tract, quite frequently the spleen, and at times the pancreas and even the left kidney. Occasionally, however, the hernia will contain no viscus and will consist simply of a mass of omentum. These hernias are often misdiagnosed or completely missed for months or even years. They may masquerade as mere diaphragmatic deformities, unexplained pulmonary densities, or even pulmonary tumors.