The white arrows show tubular gas densities in the thorax (chest). Do you think those should be there? The thorax contains the lungs and the heart. What body part is long and thin and may contain gas? Right! Those are the intestines! Those DO NOT belong in the thorax, they belong in the abdomen (where the red arrows are). Very good Doctor.
The yellow arrows show a triangular shaped soft tissue density (like an organ of some kind). Just above the yellow arrows is the heart (about the same color). What could this be? What organ looks kind of triangular when viewed from the side on a radiograph? Kidney? No, it is oval in shape. Liver? Maybe one part of the liver, but it is much larger and does not move around much. Spleen? Absolutely! This looks like a normal size and shape for a spleen on a puppy this size. One big problem though. The spleen is supposed to be in the abdomen, to the left and below where the red arrows are located. You are on a roll, you almost have the problem figured out, Doctor.
Now, what is the separation between the abdomen (belly) and the thorax (chest) of a dog? When you breathe deeply, it is said you are breathing from your ______________? Did you say Diaphragm? If you did, you are right! The diaphragm is a muscle that separates the abdomen and the thorax, keeping the organs in their own place. It is very important in breathing, as the diaphragm pulls in, air is drawn into the lungs. You have used your diaphragm quite a few times while you were reading this paragraph and you did not even know it! So if the diaphragm is torn, what do you think would happen? Absolutely, the freely moveable organs, like the intestines and the spleen can move up into the thorax cavity. This is not good. There is just the right amount of room in there for the lungs and heart and having those organs in the chest makes the lungs and the heart less able to do their job. This is called a Diaphragmatic Hernia. A hernia is any tear in a muscle that allows contents to come through it, like an umbilical (belly button) hernia.