Postdiaphragmatic disposition of the pars sympathica and major autonomic ganglia of the horse (Equus caballus)
Ghoshal, N.G.; Getty, R.
American Journal of Veterinary Research 31(11): 1951-1961
1970
ISSN/ISBN: 0002-9645 PMID: 4249950 Document Number: 23072
The morphology of the abdominal, pelvic and coccygeal (caudal) portions of the sympathetic trunk and the associated major autonomie ganglia and plexuses were studied in eight horses. The greater (thoracic) splanchnic nerve left the sympathetic trunk at or around the 6th thoracic ganglion and the lesser (thoracic) splanchnics arose variably from the last two or three thoracic ganglia. The abdominal segment did not show metameric arrangement and intermediate ganglia were frequently observed in its interganglionic rami, especially in its caudal part. The oblique communicating branches were present in the cranial lumbar segments. The origin, course, distribution and number of the lumbar splanchnic nerves varied widely; usually they were less in number than the lumbar ganglia. The pelvic segment split at or around the 3rd sacral vertebra. The communicating rami of the abdominal and pelvic segments were frequently split. The pelvic nerves arose constantly from the 3rd and 4th sacral segments, with a variable contribution either from the 2nd or 5th eacral segment or both. The impar ganglion was usually observed between the 2nd and 3rd coccygeal vertebrae.