The Anatomical Record Volume 3 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1909 Excerpt: ... THE ANATOMICAL RECORD Vol. III. DECEMBER, 1909. No. 12 THE PHYLOGENY OF THE FACIAL NERVE AND CHORDA TYMPANI.1 BY RALPH EDWARD SHELDON, Assistant Professor of Anatomy, University of Pittsburgh. With Six Figures. The structure of the human nervous system is so complex and is modified in so many ways from the normal vertebrate type that the interpretation of its morphology and function often becomes a matter of serious disagreement. The situation is further complicated by the fact that experimentation, open to the student of lower animals, is necessarily barred in an investigation of the highest. It is largely owing to these considerations that the question of the innervation of the tongue for the sense of taste is even now, after seventy years of study, one of the most disputed points in human anatomy. This discussion is for the purpose of calling attention to the ease with which a careful analysis of the data furnished by phylogenetic history will elucidate the most vexed questions of human morphology. The tongue is innervated by two sensory nerves, the glossopharyngeal and the lingual. While the former takes its course direct from the posterior part of the tongue to the petrosal ganglion, the latter is joined shortly by the chorda tympani from the facial nerve. (Fig. 6.) It would seem that the question as to which of these nerves fur 1 Address given before a joint meeting of the Chicago Neurological Society and the University of Chicago Biological Club, March 30. 1909. nishes the fibers for taste could be easily settled by their dissection in the adult, by sections of embryological material or by the observations made in clinical or other pathological cases. Such studies have, however, led to the most diverse results. Since the time of the researches of Cla...