Topographical study of the connections of the rami communicantes from the first to the fifth thoracic sympathetic ganglia

This study investigated the morphological variations and histological patterns of the rami communicantes (RCs) arising from the first to the fifth thoracic sympathetic ganglia, and considered the clinical significance of these variations. Fifty upper thoracic portions from 26 adult Korean cadavers were used in this study. There were 731 RCs arising from the first to the fifth thoracic sympathetic ganglia. They were classified into three types depending on the connection between the sympathetic ganglion and the intercostal nerves: in type I, the RCs connected the ganglion to the corresponding intercostal nerve, and in types II and III, respectively, they connected it to the nerve one level above or below the corresponding intercostal nerve. Some RCs of types I and II could not be observed without additional preliminary surgical procedures. Diverse combinations of RC types arose from the first to the fifth thoracic sympathetic ganglia, combinations of types I and III being the most common (70%) in the first sympathetic ganglion and those comprising only type I being most frequent in the other ganglia. The RCs could not be identified by the naked eye in either fresh or fixed cadavers, so they were confirmed on the basis of their histological appearance. These results are expected to improve knowledge of morphological variations of the RCs in the upper five thoracic sympathetic ganglia, and to provide helpful information for clinical management in this region. Clin. Anat. 31:1151–1157, 2018.