Availability of Ultrasongraphic Study in Larynx

Ahn, Cheol Min; Jo, Young Ho; An, Hyun Suck; Son, Hyoung Rae; Choi, Hye Jin

Abstract

BACKGROUND AND OBJECTIVES: The observation about the movements of laryngopharyngeal or surrounding structures is very important to understand the physiology of phonation or swallowing and to diagnose the disease. Many investigating methods were used but most of them were ineffective because those were invasive or indirect methods. Ultrasonographical examination of larynx can be applied, but the shortcomings of mechanics limits the usage of ultrasonographical study of larynx. Recently, the revolution of computer and videosystem made ultrasonographical study to be applied to the larynx. In this study, authors wanted to find out the availability of the ultrasonographical study of larynx.
MATERIALS AND METHODS
3.5 and 7.5 MHz probes were applied to anterior neck and the ultrasonographical findings were observed according to the various phonation types.
RESULTS
In the axial plane, the movements of bilateral vocal folds were observed. Unilateral movement of vocal cord alone was seen in the case of unilateral vocal cord paralysis. In the parasagittal plane, the movements of whole laryngopharyngeal structures were observed simultaneously. A specific tongue shape was seen on each vowel phonation. On phonation with high pitch, hyoid bone and thyroid cartilage were elevated. And thyroid cartilage was elevated and laid upon the hyoid bone moving medially. On phonation with high pitch extremely, the hyoid bone went down. On phonation loudly, echogenicity of surrounding muscles was increased.
CONCLUSION
Authors think that the ultrasonographical study can be applied to the physiologic study of phonation as well as diagnostic tools or therapeutic tools.