• Thyroarytenoid muscle;
  • motor entry point;
  • laryngeal electromyography;
  • vocal cord immobility;
  • spasmodic dysphonia


Anatomical localization of the motor entry point in the thyroarytenoid muscle

Objectives: To localize the motor entry point (MEP) of the thyroarytenoid muscle.

Methods:Eight cadaver larynges were dissected. A virtual plane was used to represent the MEP in a coordinate(X/Y/Z) system. The inferior border of the thyroid cartilage was linked to the center of the anterior arc of the cricoid cartilage (the Y-axis). The X-axis was set perpendicular to the Y-axis; the Z-axis passed through the posterior border of the thyroid lamina from the height of the insertion point.

Results: The mean X, Y, and Zcoordinates were 6.2, 9.1, and 11.0 mm, respectively. The calculated angles of the lateral and superior deflections were 29.4° and 35.8°, respectively. The calculated insertion depth, i.e., the distance from the insertion point tothe MEP, was 15.6 mm.

Conclusions: These results may help to improve the accuracy of needle insertion during diagnostic laryngeal electromyographyor laryngeal electromyography-guided injections. © 2014 Wiley Periodicals, Inc.