The locations of stapedius and tensor tympani motoneurons in the cat
Article first published online: 9 OCT 2004
Copyright © 1983 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 216, Issue 1, pages 10–19, 1 May 1983
How to Cite
Shaw, M. D. and Baker, R. (1983), The locations of stapedius and tensor tympani motoneurons in the cat. J. Comp. Neurol., 216: 10–19. doi: 10.1002/cne.902160103
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 28 DEC 1982
- facinl nucleus;
- middle ear muscle;
- inncrvation ratio;
- auditory system;
- trigeminal nucleus
The numbers and locations of motoneurons to the Stapedius and tensor tympani muscles were determined by retrograde transport of horseradish peroxidase. Stapedius motoneurons lay outside the traditionally recognized facial nucleus, in several distinct locations: (1) in the interface between the facial nucleus and the superior olive; (2) in a thin, scattered lamina of somewhat smaller cells spread dorsal to the facial nucleus; and (3) in a cluster located ventromedial to the rostral third of the facial nucleus. Some cells also lay dorsal to the superior olive or scattered in the reticular formation, just medial to the descending loop of the facial nerve. Tensor tympani motoneurons also lay outside the traditionally recognized trigeminal motor nucleus, in an areajust ventral to it. Both motoneuron pools were large, producing in-nervation ratios that establish Stapedius and tensor tympani among the most finely innervated muscles yet studied. The degree of intermingling of large and small cells in these pools may explain, in part, why it has been easier to identify slow muscle fibers physiologically in tensor tympani than in Stapedius.