Mapping Superficial Lymphatic Territories in the Rabbit

Abstract

Little is known about the anatomy of the lymphatic system in the rabbit with regard to relationships between the lymphatic vessel and lymph node. According to our previous studies in human cadavers and canines, the superficial lymphatic system could be divided into lymphatic territories. The aim of this study was to completely map the superficial lymphatic system in the rabbit. We used our microinjection technique and histological analysis for dissecting studies and recently developed indocyanine green (ICG) fluorescent lymphography for demonstrating dynamic lymph flow in living rabbits. Real-time ICG fluorescent lymphography was performed in two living New Zealand White rabbits, and direct dye microinjection of the lymphatic vessels was performed in eight dead rabbits. To assess the relationships between the vascular and lymphatic systems in rabbits, we performed radiocontrast injection into arteries in two dead rabbits prior to the lymphatic injection. The ICG fluorescent lymphography revealed eight lymphatic territories in the preauricular, submandibular, root of the lateral neck, axillary, lumbar, inguinal, root of the tail, and popliteal regions. We injected blue acrylic dye into every lymphatic vessel 0.1 mm in diameter or larger. We then dissected and chased the stained lymphatic vessels proximally until the vessels connected to the first tier lymph node. This procedure was repeated throughout the body until all the relationships between the lymphatic vessels and lymph nodes were defined. The lymphatic system of the rabbit could be defined as eight lymphatic territories, each with its own lymphatic vessels and lymph node. Anat Rec, 296:965-970, 2013. V C 2013 Wiley Periodicals, Inc.Key words: lymphatic system; indocyanine green fluorescent lymphography; microinjection; rabbits Our knowledge of the lymphatic system in animals and humans is limited and is one of the least understood aspect of the gross anatomy (Shin et al., 2003;Hadamitzky and Pabst, 2008). A better understanding of the lymphatic system is of the utmost importance in establishing the scientific basis for the clinical management of infectious diseases, lymphedema, and cancer metastasis. Since Aselli described lymphatic vessels as "lacteals" (Aselli, 1627), researchers have used mercury (Nuck, 1692;Cruikshank, 1786;Mascagni, 1787;Sappey, 1874) and dye (Gerota, 1896;Bartels, 1909) in cadaveric studies and radiocontrast medium (Kinmonth, 1952) and radioisotopes (Sherman and Ter-Pogoissian, 1953) in clinical settings to demonstrate the lymphatic system.Researchers have investigated the anatomy of the lymphatic system in various species: rats, dogs, pigs,

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