Lymphatic drainage of heart and lungs: comparison between pig and man

In its anatomy and physiology the pig is comparable with humans and its org ans can be considered for xenotransplantation. We have studied the lymphati c drainage of the heart and lungs in 15 pigs. A coloured mass was injected into the myocardium and/or beneath the visceral pleura. The first nodes col oured were directly injected again. No lymph node was observed inside the h eart and lungs. The first lymph nodes coloured were the peritracheobronchia l nodes. There was no node in front of the thoracic trachea (Barety's compa rtment in man). Left suprabronchial nodes were connected with the thoracic duct in the mediastinum. The lymphatics of the heart and lungs in the pig a re similar to those of human. Phylogenesis explains "skipping" metastases a nd the significance of N1 disease in lung cancer, as well as chylothorax oc curring after heart and lung surgery.