Anomalous fixation of the mesentery occurs fairly often. It varies from the rare primitive forms of embryonic fixation associated with nonrotation of the intestines to the common late forms of nonattachment of the mesentery of the ascending colon. Often no symptoms result, but sometimes symptoms arise owing to abnormal mobility of the ascending colon or to complications resulting from the mesenteric anomalies. Among possible complications caused by such anomalies are: intestinal obstruction caused by volvulus, intussusception or so-called internal hernia; obstruction caused by congenital peritoneal bands, and such complications as may arise from misplacement of the cecum and of the appendix.
The anomalies encountered after birth are believed to be due to arrests in fetal development. They fall naturally into one of the three stages into which fetal development has been divided by Frazer and Robbins,1 by Dott2 and by others. The present report deals only with the