Anatomical Studies on the Morphology and Topography of Cavity Lymphnodes in Pigs
Authors: ZAGRAI G. , DUMITRESCU I. , COTOR G. , MIHAI Sorina Andreea , GAGNIUC Elvira , Grama Aureliana , BELU C. , DAMIAN A. 
Published: January 2025

The lymphatic system, supported by the lymphatic vessels, is a vascular network in higher vertebrates, having essential roles, such as regulating tissue pressure, monitoring the immune system and absorbing fats from the diet. The lymphatic vessels constitute an unidirectional system that transports fluids and proteins, taking them from the interstitial space and returning them to the bloodstream.
Objectives: The objectives pursued in this study are the following: to identify the topography of the main cavity lymph nodes and the morphological and topographic variants that may occur; to identify the main interspecific histological characteristics of vessels and lymph nodes in pigs.
Materials and methods: The study was carried out on 20 animals weighing 25-30 kg, aged about 3.5 months, of both sexes. They came from private breeders. Ultrasonographic investigations were also performed on half of them. The macro- and microscopic anatomical studies as well as the ultrasonographic investigations were performed at the Faculty of Veterinary Medicine in Bucharest. For macroscopic and topographic analysis, lymph nodes in both the thoracic and abdominal cavities were examined "in situ".
Results. Caudal mediastinal lymph nodes were always fewer in number (between one and three). They were associated with the esophagus, immediately behind the tracheobronchial and ventral lymph nodes of the aorta. The afferents originated from the pericardium, the caudal part of the mediastinum and the corresponding part of the esophagus. The efferents connected to the tracheobronchial lymph nodes or could also approach some thoraco-aortic lymph nodes. The lumbo-aortic lymph nodes were located on the lateral surfaces of the aorta, starting from the diaphragmatic orifice to the origin of the deep iliac circumflex artery. The iliac lymphocenters were represented by large lymph nodes that formed a bundle at the origin of the celiac artery. Colic lymph nodes were located along the path of the right colonic artery. Splenic lymph nodes were placed on the path of the homonymous vessels. Their topography was between the aorta and the hilum of the spleen. In this sector there could be 2-4 lymph nodes, but there were others (2-5) located along the upper quarter of the spleen. The jejunal lymph nodes formed a double chain in the middle of the jejuno-ileum meso, about 30 cm long. The caudal mesenteric lymph nodes were reduced, located dorsally by the descending colon on the path of the caudal mesenteric artery.
Conclusions. In the case of mediastinal lymph nodes, the anterior ones are present, but their topography differs significantly from individual to individual. The most important groups of visceral lymph nodes are jejunal and colic. The most important parietal lymphocenter is the ileosacral one. In it, we were able to describe for the first time some individual variants, namely: lateral iliac lymph nodes dominant in volume compared to the medial ones, the absence in some cases (10%) of anorectal lymph nodes in some specimens, in which, however, a compensation was observed by the development of a chain of small units on the path of the median sacral artery.