Diverticula are known to occur in practically every portion of the digestive tract. They are most common in the colon and are frequently found, also, in the esophagus and duodenum. Diverticulosis of the small bowel, however, is rare. A recent report by Benson, Dixon, and Waugh (1) states that at the Mayo Clinic, from 1909 to 1942, inclusive, there occurred 122 cases of non-meckelian diverticula of the jejunum and ileum, an average of less than 4 per year. These authors indicate that, in addition, there are only about 200 other recorded examples in the medical annals. Case (2) was able to find but (36 proved cases in the literature in the eighty-year period from 1844 to 1924. In our clinic at the Boston City Hospital, we have observed a series of 25 cases of diverticulosis of the jejunum and ileum, all of which were seen in a period of two and a half years, from January 1942 to July 1944, and were diagnosed during routine studies of the gastro-intestinal tract with the opaque meal. Because of the relative infrequency of diverticula of the small bowel, it was felt worth while to record the clinical and roentgen manifestations of these cases. Pathogenesis Diverticula of the small intestine, in common with other types of diverticulosis, may be either congenital or acquired. In the congenital type, the pouch comprises all the layers of the small bowel, while in the acquired group there is a herniation of the mucosa through a defect in the muscular layer. Diverticula are usually, although not necessarily, found along the mesenteric border of the intestine. They may be either single or multiple. The size varies from a few millimeters to several centimeters in diameter. The pouches are usually smooth and rounded; in some instances they appear oval or elongated. The communication with the lumen of the small bowel is variable and may be large or small. The diverticula occur in any portion of the small bowel from the duodenojejunal junction to the ileocecal valve. The upper and middle thirds of the jejunum are the most usual sites, the ileum being the least frequently involved. Inflammatory changes resulting in diverticulitis may be due to irritation or occlusion by fecal concretions and foreign bodies. Edema and local swelling produce stasis in the diverticulum. The inflammation tends to involve adjacent segments by direct extension and is accompanied by pain, tenderness, and spasm. Perforation may supervene with the formation of either a localized or, more frequently, a generalized peritonitis. In those instances in which the local inflammatory process subsides prior to perforation, areas of fibrosis with partial stenosis or complete obstruction may subsequently develop. Etiology The chief predisposing factors of diverticulosis of the small intestines may be summarized briefly as follows: