Anatomic variations of the intrathoracic nerves and the neural connections of the second and third thoracic sympathetic ganglia to the brachial plexus.

ABSTRACT

INTRODUCTION: This study investigated morphological variations of the intrathoracic nerves and the neural connections of the second and third thoracic sympathetic ganglia to the brachial plexus based on the existence of the intrathoracic nerves and the rami communicantes. MATERIALS AND METHODS: Fifty thoracic sympathetic trunks from 26 Korean adult cadavers were used. RESULTS: The first intrathoracic nerve connecting the first and second thoracic nerves was observed on 36 sides (72%), and the second intrathoracic nerve connecting the second and third thoracic nerves was found on three sides (6%). There were either one (62%) or two (10%) first intrathoracic nerves, and only one second intrathoracic nerve (6%). The neural connections of the second and third thoracic sympathetic ganglia to the first thoracic nerve were classified into three types based on the existence of the intrathoracic nerves Type I (68%) had only the first intrathoracic nerve, Type II (26%) had no intrathoracic nerve, and Type III (6%) had both the first and second intrathoracic nerves. Types I, II, and III were further subdivided into 10, 6, and 3 types, respectively, according to the types of the rami communicantes arising from the second and third thoracic sympathetic ganglia. CONCLUSIONS: Improved knowledge of the variations in intrathoracic nerves and upper thoracic sympathetic ganglia will be helpful to thoracic surgeons when they are disrupting the sympathetic supply to the hand for treating palmar hyperhidrosis, and contribute to successful diagnoses and treatments.