The three-dimensional microstructure of intramural lymphatics in the canine large intestine.

The three-dimensional microstructure of the intramural lymphatics of canine large intestine was clarified micrographically. After direct injection of India ink into the colon wall, we prepared 2 less than 3cm full-thickness transparent specimens of the opened colon wall and transparent sections. Lymph vessels were distinguished from blood vessels by intraarterial injection of cinnabar ink. A stereomicroscope was used for observation, and stereograms were reproduced. Lymph vessel networks were present in the shallow and deep layers of the lamina propria mucosae and the deep layer of the submucosa. The lymph vessel networks in the lamina propria mucosae were present immediately beneath the blood capillary networks. The thickest lymph vessels and the densest network appeared in the submucosa. From the submucosa, some of the lymph vessels existed immediately to merge into the collecting trunks and other lymph vessels which compose a minor pathway existed along lymph vessels in the muscular layer and finally merged into the collecting trunks in the subserosa.