Anatomical variations of the second thoracic ganglion.

In recent years the second thoracic ganglion has gained anatomical significance as an important conduit for sympathetic innervation of the upper extremity. Thoracoscopic excision of the second thoracic ganglion is now widely recognized as affording the most effective treatment option for palmar hyperhidrosis. This study recorded the incidence, location and associated additional neural connections of the second thoracic ganglion. Bilateral dissection of 20 adult cadavers was undertaken, and all neural connections of the second thoracic ganglion were recorded. Nineteen cadavers (95%) demonstrated additional neural connections between the first thoracic ventral ramus and second intercostal nerve. These were classified as either type A (47.5%) or type B (45%) using the intrathoracic ramus (nerve of Kuntz) between the second intercostal nerve and the ventral ramus of the first thoracic nerve as a basis on both right and left sides. The second thoracic ganglion was commonly located (92.5%) in the second intercostal space at the level of the intervertebral disc between the second and third thoracic vertebrae. Fused ganglia between the second thoracic and first thoracic (5%) and stellate (5%) ganglia were noted. These findings should assist the operating surgeon with a clear knowledge of the anatomy of the second thoracic ganglion during thoracoscopic sympathectomy with a view to improving the success rate for upper limb sympathectomy.