[An unknown role of the ligament layer of the conus elasticus during phonation?].
The investigation of the intoning vocal folds with the help of Cermák's mirror in as early as the 19th century and also their ensuring records by means of a stroboscopic film have discovered the fact that the front vibrating part of the vocal folds becomes shortened in high frequencies. This information has been ignored since about the 60ies of the 20th century. The aim of the present paper is to verify the shortening of the front vibrating part of the vocal folds and to recall this fact. Approximately in two octaves we have measured the virtual images of a video stroboscopic record. Our results are comparable with similar measurement resulting from stroboscopic investigation and confirm the hypothetic role of the ligament layer conus elasticus.