Crohn´s disease, as described by Crohn, Ginzburg and Oppenheimer in 1931, was a disease confined to the distal part of the small bowel, and hence called "regional ileitis" or "terminal ileitis". This is still a typical presentation of this disease. These pictures show inflammation and ulcers in the terminal ileum caused by Crohn´s disease.

A long segment of the distal ileum affected by Crohns disease in a patient astonishingly symptomfree.

The Valvula Bauchini is almost always involved in this typical presentation of Crohn´s disease.

Very often small aphtous changes in the caecum (in the pictures above, in the middle picture the appendix aperture is seen in the lower part of the picture) and in the rest of the colon (pictures below) can be seen in colonoscopy in patients with a typical presentation of Crohn´s disease. These changes could not be identified in the 30´ies. It was not until 1960 when Lockhart-Mummery and Morson demonstrated the changes of Crohn´s disease in the colon.

Examples of typical aphtoid ulcers in the colon.

Severe ulcers in the sigmoid colon due to Crohns disease

When the mucosa in the colon is partly or totally destroyed by Crohn´s disease and then regenerates, the result is sometimes a striking inflammatory polyposis as in these pictures.