The vocal ligaments insert at the anterior and posterior commissures of the larynx. These structures fulfil
biomechanical functions, balancing the different elastic moduli of tendon, cartilage or bone and undergo
age-related changes that may be responsible for voice changes with increasing age. The aim of this study was
to analyse the insertion structures of the vocal ligaments by means of macroscopic, histological,
immunohistochemical and electron-microscopic methods and to draw conclusions from age-related structural
changes on a functional basis. Investigations were carried out on the larynges of 22 males and 15 females
(aged 1–95 y). In adolescence, the insertion zone of the vocal ligament tendon, a dense network of
connective tissue rich in sulphated glycosaminoglycans at the thyroid cartilage, is characterised by a layer
between tendon and cartilage comparable to fibrocartilage. The insertion zone lacks a perichondrium.
Collagen fibrils of the vocal ligament tendon penetrate directly into the thyroid cartilage. In the insertion
area, the chondrocytes are surrounded by collagen fibrils, which show positive reactivity to antibodies
against type I and type III collagen. Sulphated glycosaminoglycans are integrated between the collagen
fibrils. In the area of the posterior glottis, elastic cartilage rests like a cap on the hyaline base of the
arytenoid cartilage. There is no distinctive border between the structures. With increasing age, ossification of
the laryngeal skeleton occurs, involving hyaline cartilage at the posterior glottis and hyaline and
fibrocartilage at the anterior commissure. At the same time, a loss of sulphated glycosaminoglycans is
observed inside the vocal ligament tendon. Advanced ossification of the laryngeal skeleton, particularly in
the area of the commissures, an increasing loss of glycosaminoglycans in the vocal ligament tendon and
changes in the elastic tissue reduce the elastic modulus between tendon, cartilage and bone, thus ‘stiffening’
the insertion zones, which could be one factor among others favouring voice changes with advancing age.
