Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1968 A comparative anatomical study of the cranial nerves in goat, sheep and bovine (Capra hircus, Ovis aries and Bos taurus): their distribution and related autonomic components Hugo Pereira Godinho Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Animal Structures Commons, and the Veterinary Anatomy Commons Recommended Citation Godinho, Hugo Pereira, "A comparative anatomical study of the cranial nerves in goat, sheep and bovine (Capra hircus, Ovis aries and Bos taurus): their distribution and related autonomic components" (1968). Retrospective Theses and Dissertations. 3241. https://lib.dr.iastate.edu/rtd/3241 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. This dissertation has been microfilmed exactly as received 68-10,461 GODINHO, D. V. M., Hugo Pereira, 1935- A COMPARATIVE ANATOMICAL STUDY OF THE CRANIAL NERVES IN GOAT, SHEEP AND BOVINE (CAPRA HmCUS, OVIS ARIES AND BOS TAURUS); THEIR DISTRIBUTION AND RELATED AUTONOMIC COMPONENTS. Iowa State University, Ph. D., 1968 Anatomy University Microfilms, Inc., Ann Arbor, Michigan A COMPARATIVE ANATOMICAL STUDY OF THE CRANIAL NERVES IN GOAT, SHEEP AND BOVINE (CAPRA HIRCUS, OVIS ARIES AND BOS TAURUS); THEIR DISTRIBUTION AND RELATED AUTONOMIC COMPONENTS by Hugo Pereira Godinho V./M, A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Veterinary Anatomy Approved; Signature was redacted for privacy. In Charge of Mkjor Work Signature was redacted for privacy. Head of Major Dep rtment Signature was redacted for privacy. Dean of Graduate Colleg Iowa State University Ames, Iowa 1968 PLEASE NOTE: Figure pages are not original copy. They tend to "curl". Filmed in the best possible way. University Microfilms. ii TABLE OF CONTENTS Page INTRODUCTION 1 REVIEW OF LITERATURE 4 .MATERIAL AND METHODS 119 RESULTS 126 DISCUSSION 331 SUMMARY AND CONCLUSIONS 371 BIBLIOGRAPHY 378 ACKNOWLEDGMENTS 390 1 INTRODUCTION The present investigation is primarily a macroscopic study of the cranial nerves of the domestic ruminants (goat, sheep and ox) and is intended to give an account of the most frequent pattern of their course and distribution. It is a part of the systematic investigation that the Department of Anatomy, at Iowa State University, is conducting on the peripheral nervous system of our domestic animals. To accomplish the proposed task, gross dissections of embalmed specimens were performed which required, in special cases assistance of a dissecting microscope, examination of decalci­ fied specimens or histological preparations, following the approach used previously for the cranial nerves of the pig (Godinho, 1966). The search of literature revealed that a great deal has been written on this subject which has never ceased to fascinate anatomists. However, only a few and scattered references are concerned with the species under investiga­ tion, particularly the goat. One of the earliest recorded accounts is the work of Galen (ca. A.D. 130-201) who gave a description of the nerves in his book "On Anatomical Procedures". A synopsis of Galen's long treatise is presented by Goss (1966). Another work on historical aspects of the cranial nerves was recently published by Rucker (1966). In the present 2 study, only those publications directly concerned with the cranial nerves of the domestic ruminants are included in the chapter of Review of Literature. However, references are made to other species when discussing areas of discrepancies encountered in the literature consulted. As demonstrated by the number of specimens utilized, emphasis was given to the goat and sheep. The cranial nerves of these animals have been described by standard veterinary anatomical textbooks in a comparative manner in which superficial remarks are made about the actual anatomical disposition (Chauveau and Arloing, 1905; Zimmerl, 1930; Martin and Schauder, 1938; Ellenberger and Baum, 1943; Bruni and Zimmerl, 1951; Sisson and Grossman, 1953; \ Dobberstein and Hoffmann, 1964; Habel, 1964; Koch, 1965 and Schwarze, 1965). Most of these books present the ox as the "basic animal" for ruminant anatomy while the anatomy of the sheep and goat is only partially and comparatively described, if at all. This practice usually leads the readers, especially the veterinary students, to assume that the numerous structures observed in sheep and goat but left without compari­ son are similar to the bovine. Thus, the scarcity of informa­ tion recorded in both the literature and anatomical textbooks indicates the necessity of having a succint and accurate description of the cranial nerves in the domestic ruminants. The study of the vagus nerve in the present investigation was conducted as far as the retropharyngeal region. In the 3 cervical and thoracic regions it has recently been investigated by McKibben (1966) whereas its abdominal distribution was thoroughly studied by several investigators, including Foust (1929) and Habel (1956). With respect to the nomenclature, the author followed, as close as possible, that approved by the 6th Meeting of the World Association of Veterinary Anatomists held in Giessen and Wiesbaden, Germany, during August, 1965. The terms pertaining to the cranial nerves or related structures in the head have been translated into their English equivalent. The Latin form is maintained only when an Anglicized correspondent is not available or currently used. Lastly, it is hoped that the present study may clarify some of those areas of disagreement found within the literature or between this and the present findings, therefore contributing to a better morphological understanding of the cranial nerves in domestic ruminants. 4 REVIEW OF LITERATURE Olfactory Nerves The olfactory nerve of the bovine, according to McLeod (1958), consisted of a large number of fibers which did not form a trunk. The fibers were nonmedullated and were from cells located in the mucosa of the olfactory region of the nasal cavity and from the vomeronasal organ. The fibers were enclosed in extensions of the meninges, entered the cranial cavity through the cribriform foramina and joined the anterior surface of the olfactory bulb. According to Kawata, Okano and Ishizuka (1962) the sensory nerve distribution on the epithelium of the ventral turbinate of the sheep was rather scanty. The sensory nerves terminated in single unbranched fine strands. In the lamina propria and submucosa various kinds of nerve elements were observed among the vessels and the aggregates of the glands. The ventral turbinate, histologically, was roughly homologous to the dorsal turbinate. Countless olfactory cells were/ observed in the epithelium of part III (caudal third) of the ethmoturbinate. The cells decreased in number in part II (middle third); and, in part I (cranial third) the epithelium was composed of ciliated cells and contained almost no olfactory cells. 5 Terminal nerves Johnston (1914) described the nervus terminalis in man and in some animals such as horse, pig, sheep, porpoise, and monkey. He examined three brains of the adult sheep. The nerve was not found in the first, but was present in the other two. In one of these brains there was a single strand on the right side and two stands on the left. One of the latter strands presented three conspicuous ganglion-like enlargements. Upon staining and mounting these proved to be true ganglia. The nerve of the right side contained single ganglion cells scattered along its course, two collections of six to eight cells each and a ganglion at its distal end larger than one of the three on the left side. A piece of the left nerve, treated in Von Rath's fluid, showed a single, lightly medullated fiber. According to Larsell (1918) the nervus terminalis of the beef lay mediad to the olfactory nerves, between the meninges and the ventral brain surface. Running parallel with it were branches of the anterior cerebral artery. In the numerous brains examined there was considerable variation in the relation of the different strands which, by their union, formed the main nerve bundle. This variation was found not only when comparing one brain with another, but also when comparing the two nerves of the same specimen. In some cases the strands were independent up to a short distance from the forward margin of the hemispheres, in other cases the bundle was formed much further caudad. For the greater part of its 6 course the portion of the nerve present in the specimens was covered by meningeal membranes. It emerged to the outer surface of the arachnoid coat at about the point where the cerebral hemispheres begin to curve upward. At this point the nerve was always compact in a single bundle. This bundle, after emerging, lay free on the surface of the arachnoid. The appearance of the free end indicated that it had been stretched and broken in removing the brain from the cranial cavity. Several ganglionic swellings were visible, the largest one in the brain from which the figure was drawn, at the point where the nerve crossed the artery. Just caudad to this ganglion the bundle divided into two strands. A short distance rostral to this ganglionic mass, a similar strand was given off from the main trunk. These strands followed the branches of the anterior cerebral artery ramifying to the secondary branches of these vessels, and at intervals they gave off fine twigs which penetrated into the muscular walls of the arteries. Several of the strands were traced continuously to the points where the, respective arteries dipped into the fissures. On the same brain, and on others, similar strands were found on all the arteries examined in this region of the brain, both on the ventral surface and in the sagittal fissure.