[The lymph vessel system of the mouth cavity and pharynx]

The understanding of pathological processes involving the lymphatic system of the upper digestive tract requires a detailed knowledge of the lymphovascular architecture of this region.

The lymphatic system of the upper digestive tract was examined in 390 patients by different methods such as light microscopy, electron microscopy, histochemistry, and indirect lymphography.

The mucous membrane of the upper digestive tract is permeated by two communicating lymphatic networks with regionally varying density. There are no areas without lymphatics. The lymphatic fluid of the nasopharynx flows from the posterior wall mainly towards the retropharyngeal and accessory lymph nodes (level II). The lymphatic flow from the buccal mucous membrane, the anterior floor of the mouth, the oral tongue, and the hard palate mostly drains toward the submandibular and craniojugular areas. Lymphatic fluid from the tonsils, the soft palate, and the hypopharynx flows primarily to the deep cervical lymph nodes (level II and III).

These results are a basis for the understanding of a) secondary lymphatic edemas and b) frequency and direction of lymphogenous metastasis of carcinomas in this region. The direction of metastasis usually follows the physiologic lymphatic drainage. Metastasis towards untypical areas can in most cases be explained by an alteration of the lymphatic flow secondary to inflammation, radiotherapy, previous surgery, and subsequent scar formation or tumor growth.