The lymphatic system of the major head and neck glands in rats.

Many studies concerning therapy and also investigations on lymphogenic metastatic spread of head and neck malignancies require animal models. This article completes the existing findings with regard to the lymphatic system of the head and neck region of the rat. Investigations (light microscopy, immuno-histochemistry, enzyme histochemistry, lympho-graphy) on architecture, distribution and density of the intraglandular lymphatic flow of the major head and neck glands (infraorbital lacrimal gland, extraorbital lacrimal gland, Harderian gland, parotid gland, major sublingual gland, mandibular gland and thyroid gland) in rats were performed. Architecture of the seven major head and neck glands in rats do not differ from other regions of the upper aerodigestive tract. While the Harderian gland shows the highest density of lymphatics, within the major sublingual gland only scare lymph vessels could be identified. Distribution and density of initial lymphatics influence directly the transmission of inflammatory and malignant diseases. The presented results are the morphologically and anatomically basis to initiate further investigations in the rat animal model emphasizing special questions concerning the lymphatic system of the major head and neck glands e.g. lymphatic drainage and new treatment concepts in cases of lymphogenic metastatic spread.