Relationship of the posterior cricoarytenoid muscle to the posterior cricoid lamina

OBJECTIVE: Early experiments in functional electrical stimulation of the posterior cricoarytenoid muscle (PCA) in human beings have involved placement of the electrode along the undersurface of the PCA. The anatomy of the posterior cricoid lamina (PCL) was examined to obtain a quantitative understanding of this region. METHODS: Thirty fresh-frozen cadaver larynges were dissected. Measurements of the cricoid cartilage and PCA were obtained with a caliper or calibrated probe. RESULTS: Twenty male and 10 female adult larynges were examined. Sex differences were found for the height of the PCL. All larynges had approximately 4 mm of exposed cartilage along the inferior surface of the PCL. The origin of the PCA on the PCL was thinner in the medial-vertical attachment than in the inferior-horizontal. The average inferolateral to superomedial diagonal width of the PCA was 4 mm greater in the male than in the female larynges. Asymmetry between the left and right sides was seen. CONCLUSIONS: The PCA can be divided into 2 muscle groups based on its origin on the PCL as well as its insertion into the muscular process of the arytenoid. The quantitative information obtained has implications for electrode design and placement for laryngeal stimulation.