Thoracic sympathetic trunk

The sympathetic trunks (sympathetic chain, gangliated cord) are a paired bundle of nerve fibers that run from the base of the skull to the coccyx.

The sympathetic trunk (T1-L2) travels in a downward direction from the skull, just lateral to the vertebral bodies. It interacts with the spinal nerves or their ventral rami by way of rami communicantes.

The superior end of it is continued upward through the carotid canal into the skull, and forms a plexus on the internal carotid artery; the inferior part travels in front of the coccyx, where it converges with the other trunk at a structure known as the ganglion impar.

Along the length of the sympathetic trunk are ganglia known as paravertebral ganglia.

The sympathetic trunk is a fundamental part of the sympathetic division of the autonomic nervous system. It allows nerve fibres to travel to spinal nerves that are superior and inferior to the one in which they originated. Also, a number of nerves, such as most of the splanchnic nerves, arise directly from the trunks.