Comparison of human, canine, and ovine laryngeal dimensions.

Geometric measurement of the laryngeal skeleton is a fundamental step in laryngeal studies, especially in biomechanical modeling. Traditionally, canine larynges have been used as models of the human larynx because of their similarity in size and gross structure, but the search continues for an alternative model because of the diminishing availability of the canine species for research in the United States. In this report, a revised method for defining and labeling laryngeal framework parameters is proposed. Ovine laryngeal cartilages were measured, and the measurements were compared to those of human and canine cartilages previously reported in the literature. The ovine cricoid, thyroid, and arytenoid cartilages were significantly different from the human and canine cartilages. Also, the lack of a definite border between the true and false vocal folds revealed that the ovine model may not always be suitable for a direct comparison to the human larynx in phonation.