[The larynx: an anatomical and functional echographic study].
PURPOSE: To investigate the capabilities of US in morphological and functional studies of laryngeal structures. MATERIALS AND METHODS: We examined 50 healthy subjects (30 women and 20 men) ranging in age 23 to 74 years; 17 of them were professional opera singers. The patient was laid supine, with his/her neck in marked hypertension, and images were acquired with the vocal cords at rest, and during quiet breathing inspiratory and expiratory standstill, Valsalva, and wording of "e" and "o". We used 7.5-12.0 MHz probes to perform (para)median axial scans with anteroposterior and caudocranial US beam incidence. RESULTS: All the anatomical structures that could be measured were clearly demonstrated. The length of the true vocal cords was 16-28 mm in women and 20-23 mm in men and their wideness 7-15 mm to the dorsal end 2-4 mm to the ventral and; maximum thickness ranged 2-10 mm. The respiratory space varies 2-8 mm in the different phases of respiration and speech. In the 17 opera singers we found agreement between length of the vocal cord compass: basses had 30-33 mm and tenors 21-25 mm. DISCUSSION AND CONCLUSIONS: In addition to the advantages US is known to provide, it can also permit accurate measurements of the anatomical structures of the larynx and respiratory space at rest and in the dynamic phase, which are important data in some conditions (e.g., cord paralysis) or follow-up of drug or rehabilitation treatment. Finally US can permit to detect atypical situations such as those in false/true vocal cords hypertrophy and abnormal cord growth.