Arrangement of motoneurons innervating the intrinsic laryngeal muscles of cats as demonstrated by horseradish peroxidase

Abstract

After HRp injection into the posterior cricoarytenoid (PCA), the thyroarytenoid (TA), the lateral cricoarytenoid (LCA) and the interarytenoid (IA) muscles, labeled neurons were identified in the nucleus ambiguus ipsilaterally. The motoneurons for the cricothyroid muscle (CT) were found ipsilaterally in the retrofacial and ambiguus nuclei. The labeled cell columns of PCA, TA, LCA and IA were situated more caudal than that of CT in the order of PCA, TA, LCA and IA. In the nuc. ambiguus, the motoneurons of CT showed compact form and were located in the ventral part, those of PCA were aggregated and occupied the middle part, those of TA were scattered and were seen in the dorsal part, and those of LCA and IA were sparse and were recognized widely in the nucleus.