Morphological Variations of the Human Interarytenoid Muscle

This study investigated morphological variations of the transverse and oblique bellies of the interarytenoid muscle and their microstructures in humans. Forty-seven larynges from 50 formalin-embalmed cadavers were dissected to expose the arrangement of muscle fibers of the interarytenoid muscle. Histological sections of the laryngeal frame including the arytenoid cartilage and adjacent connective tissues were observed in three larynges. Forty larynges(85%) showed the typical morphology with superficial oblique and deep transverse bellies of the interarytenoid muscle. The boundaries of the oblique and transverse bellies of the interarytenoid muscle were atypical in the other seven cases (15%). In one case, a muscle belly originated from the cricoid cartilage medial to the posterior cricoarytenoid muscle and caused a height discrepancy of the arytenoid cartilage. Histological observations revealed that most of the muscle bellies of the transverse arytenoid muscle inserted to the muscular process of the arytenoid cartilage, whereas some muscle fascicles dispersed into the connective tissues of the lateral laryngeal frame. Occasionally, accessory muscle bellies vertically arose deep to the transverse arytenoid muscle. The results of this study will contribute to advance relevant anatomical knowledge for accurate diagnosis and treatment planning of laryngeal disorder such as dysphonia. KCI Citation Count: 0