Arrangement of Motoneurons Innervating the Intrinsic Laryn-Geal Muscles of Cats as Demonstrated by Horseradish Peroxidas

Abstract

After HRP injection into the posterior cricoary-tenoid (PCA), the thyroarytenoid (TA), the lateral cricoar-ytenoid (LCA) and the interarytenoid (1A) 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 1A were situated more caudal than that of CT in the order of PCA, TA, LCA and 1A. 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 1A were sparse and were recognized widely in the nucleus.