Lymph Vessels of the Spleen
Of the lymph vessels of the spleen (Figure 26: 4), only those of the spleen capsule are considered, as the splenic parenchyma has no lymph vessels – in this respect, the dog is the same as the cow (see Baum ).
I would like to point out that it is very easy to mistake the small veins that fill when injections are made into the splenic parenchyma for lymph vessels. Because of this, I have therefore only described a vessel as a lymph vessel when I have been able to trace it to the associated lymph node.
The spleen capsule has lymph vessels, but these are very difficult to inject, likely because the capsule is very thin. These lymph vessels can be filled more easily on the visceral surface than on the parietal surface of the spleen; as for the latter, it is extremely difficult to succeed. I have not been able to conclude anything definite about the formation of a network of these lymph vessels, despite very careful examination and observation. It must be assumed a priori that these lymph vessels form networks, but I have not been able to prove that they exist macroscopically. The lymph vessels run on the visceral surface of the spleen directly from the site of injection to either the hilus of the spleen or to the point of attachment of the omentum to the spleen, and then from the splenic hilus, accompanied by the splenic veins, to drain to the splenic lymph nodes (Figure 26: d, d’) and, if there are several lymph nodes, to all of them. The lymph vessels were not observed to bypass the lymph nodes.