Geometric structure of the human and canine cricothyroid and thyroarytenoid muscles for biomechanical applications

The geometric structure of the cricothyroid (CT) muscle and thyroarytenoid (TA) muscle was quantified in 6 human and 3 canine larynges. Each muscle wa s divided into a series of fiber bundles. With a 3-dimensional micrometer p robe, the coordinates of the origin and insertion of each bundle were measu red before dissection. It was found that the mass of the CT muscle in the d og was 1.463 +/- 0.280 g, which was significantly greater than the 0.9423 /- 0.123 g found in the human. This was a result of the cross-sectional are a of the canine CT muscle being 105.3 +/- 11.6 mm(2) instead of the 73.8 +/ - 7.4 mm2 found for the human. However, the ratios of CT/TA mass and cross- sectional area between the two groups were not significantly different, sug gesting that the two muscles grow proportionally.