Abstract
The uniformity of mucosal morphology within the distal duodenum and the first loop of jejunum, ie, the area usually biopsied, was examined at necropsy in 116 children. In those with no evidence of gastrointestinal disease there was no significant variation within this area, but in 25 children with mucosal abnormality, variation occurred within a small area. The crests of the plicae circulares were more often more severely abnormal than the area in the valleys between. Owing to the small size of biopsy specimens, it is apparent from this study that such specimens may not be representative of the proximal small intestinal mucosa in children suffering from the disorders of the small intestine encountered in this study.