Cricothyroid distance and vocal pitch. Experimental surgical study to elevate the vocal pitch.

To establish an experimental basis for surgical approximation of the anterior cricothyroid distance which aims at raising the vocal pitch, the relationship between vocal pitch and the cricothyroid distance was analyzed in voices produced with excised human larynges (four male and two female larynges). Within the framework of the experimental conditions, the following conclusions were drawn: 1) The vocal pitch expressed in semitones was almost linearly related to the cricothyroid distance, with an increase of 0.15 to 0.90 semitones per milimeter of cricothyroid approximation. 2) The rise in vocal pitch reached a plateau when the force applied to shorten the cricothyroid distance reached 30 to 50 gm.