Valves in the subsidiary lymph trunks in the neck

Abstract

Introduction: The thoracic duct drains both lymph and chyle into the confluence of the great veins in the root of the neck. The venous termination of the duct is protected from retrograde flow of blood by valves. However, little attention has been focused on the presence or absence of valves in the subsidiary lymph trunks in the neck. Aims: The aim of this study was to determine whether there are valves in the subsidiary lymphatic system in the neck. Material and methods: The left side of the neck was explored in ten formalin-fixed cadavers. Subsidiary lymphatic trunks were carefully preserved for stereomicroscopic examination. Results: Eight subsidiary trunks were identified comprising four jugular, two subclavian and two bronchomediastinal trunks. Both subclavian lymph trunks drained directly into a vein. A bicuspid ostial valve was present at the termination of the trunks. The bronchomediastinal and jugular trunks drained into the thoracic duct prior to its venous termination. Valvular structures were identified along the bronchomediastinal trunks and at their termination with the thoracic duct. No valves were identified in the jugular trunks. Conclusion: The absence of valves in the jugular lymph trunks is proposed as a possible contributory factor in the creation of chyle leaks following neck dissections. Copyright 2002 European Association for Cranio-Maxillofacial Surgery. Published by Elsevier Science Ltd. All rights reserved.