Electron microscopy of myenteric nevrves in Hirschsprung's disease and in normal bowel.

The ultrastructure of the myenteric nerves of colon and rectum removed from 10 children with Hirschsprung's disease has been studied and compared with normal infant bowel. Distal aganglionic (Hirschsprung) bowel often showed a rich supply of nerves within the muscle layers and there was no obvious morphological abnormality of constituent axons. The numbers of nerves diminished as more proximal parts of the bowel were examined and the fewest nerves were found where ganglia first appeared. These ganglia were similar in structure to the ganglia of normal bowel, and a striking feature of them all was the absence of collagen between constituent neuronal units. The larger nerve trunks of aganglionic bowel frequently contained myelinated axons and these have been observed within the myenteric plexus of normal rectum. This study supports previous histochemical investigations of the nerves in bowel from patients with Hirschsprung's disease and indicates that the condition is due to a complex and variable abnormality of the arrangement of the nervous tissue of the bowel wall, involving myenteric nerves as well as ganglia.