Premature termination of the sympathetic chain

The sympathetic chain serves to distribute visceral efferents and afferents over the entire body. The sympathetic chain courses from the base of the skull to the coccyx and sends branches to distribute along spinal nerves and a number of visceral nerves that distribute to cardiac muscle, smooth muscle and glands. During dissection of the posterior abdominal wall, we identified a rare variation of the sympathetic chain. In this subject, the sympathetic chain failed to send grey rami to the L2-4 spinal nerves and terminated by joining the S1 anterior ramus. Such a variation has only been reported once in the literature in 1895. We provide both schematic and photographic documentation of this variation and propose a number of possible circuits whereby visceral axons can reach their target despite these anatomical barriers.