Objectives: Study and detailed description of the large connections between the normally recurrent inferior laryngeal nerve (RILN) and the sympathetic trunk (ST) because these may be mistaken for a nonrecurrent inferior laryngeal nerve (NRILN).
Study design: Morphologic study of adult human necks.
Methods: The necks of 144 human, adult, embalmed cadavers were examined (68 males, 76 females). They had been partially dissected by Cambridge preclinical medical students and then further dissected by the authors using magnification. The RILN, the ST, and their branches were identified and dissected. A total of 277 RILNs and STs (137 rights, 140 lefts) were observed.
Results: A communicating branch (CB) with a similar diameter to the RILN occurred between the ST and the RILN in 48 of the 277 (17.3%) dissections, 24 from the 137 (17.5%) right dissections, and 24 from the 140 (17%) left dissections. In 12 cases, the CB was bilateral. The CB arose from the superior cervical sympathetic ganglion in 3 of the 48 (6.25%) cases, from the middle ganglion in 10 (21%) cases, from the stellate ganglion in 3 (6.25%) cases, and from the ST in 32 (66.6%) cases. One (0.36%) NRILN associated with a right retro-esophageal subclavian artery (arteria lusoria) was found.
Conclusions: 1) The CB between the RILN and the ST may have a diameter and course similar to an NRILN and may be confused with it. 2) The occurrence of the CB is greater than the occurrence referred to in previous studies. 3) The occurrence of the CB is similar by side and sex. 4) The CB may arise at different levels from the cervical ST and ganglia and end in the thyroid area. 5) Other neural elements may also be confused with an RILN, such as the cardiac nerves and the collateral branches from an NRILN to the trachea and esophagus.