STRUCTURE AND FUNCTION OF VENTRAL VOCAL F OLD INSERTION FROM A CLINICAL POINT-OF-VIEW

Background: Spread of cancer at the ventral vocal fold insertion zone has been discussed controversially until today, One reason for this is the so far insufficient knowledge of the anatomical structure and fun ction of the insertion zone, Methods: The present study analyses the s tructures of laryngeal anterior commissure by means of histological, i mmunohistochemical and electron microscopical methods. Investigations are performed on vocal cords of 17 male and 13 female (aged 21-88 year s) in three planes. Results: The vocal ligament inserts at the anterio r commissure via two characteristic structures: the noduli elastici, w hich consist of two different morphological zones, and the vocal ligam ent tendon, a dense mesh of connective tissue rich in sulfated glycosa minoglycans, In the lower part of noduli elastici collagen and elastic fibres form a meshwork around embedded cells; in the upper part fibre s are running in parallel. The vocal ligament tendon is connected to t he thyroidal cartilage or bone by fibrocartilage, This area lacks a pe richondrium or periosteum. At the beginning of osteogenesis vessels of plica vocalis penetrate the bony thyroidal skeleton and contact with extralaryngeal vessels. Conclusions: Connective tissue cells of the in sertion zone and extracellular matrix components formed by these cells fulfil biomechanical functions by equalizing the different elastic mo duli of tendon, cartilage or bone. Ventral spread of vocal fold carcin omas is made possible by the lack of periosteum in the insertion zone as well as ossification and associated vascularisation of the thyroid cartilage.