Attachment of some internal laryngeal muscles at the base of the arytenoid cartilage.

The attachments of the lateral cricoarytenoid muscle, thyroarytenoid muscle and interarytenoid muscle at the base of the arytenoid cartilage were studied in six adult larynges. Fresh specimens were treated by the acetylthiocholine method, sections were made with a freezing microtome and stained with Van Gieson stain. The muscle fibres could thus be traced to their fibrous tendinous attachments. The extent of attachment of each muscle at the base of the arytenoid was traced and its relationship to the maximum concavity of the arytenoid articular facet was computed. The lateral cricoarytenoid muscle attachment extends anteromedially from the muscular process but falls short of the anterior border with a variation of 5,800M-7,800M. These variations are statistically significant. The thyroarytenoid and interarytenoid muscles' attachments show similar variations as described and discussed. The interpretation of these results is discussed and conclusions are drawn as regards the influence of these variations on the function of the glottis.