Relationship between Zuckerkandl's tubercle and the inferior laryngeal nerve including the laryngeal branches.

Purpose: Zuckerkandl's tubercle (ZT) is the most posterior extension of the lateral lobes of the thyroid gland in the area of the ligament of Berry. We investigated the relationship between ZT and the inferior laryngeal nerve (ILN), including the laryngeal branches.

Methods: We examined 40 specimens (80 sides) from 24 male and 16 female cadavers aged between 40 and 89 years at the time of death. The ZTs were graded according to Pelizzo as grade 0, unrecognizable; grade 1, only a thickening of the lateral lobe; grade 2, smaller than 1 cm; or grade 3, larger than 1 cm.

Results: First, we classified ZT into three groups according to its location, and then we investigated the relationship between ZT and the ILN, including the laryngeal branches. Zuckerkandl's tubercle was located in the middle third of the thyroid gland in 46 of 52 sides defined as grade 2 or 3. We observed that some of the tubercles passed over the ILN, some passed over the laryngeal branches, and some passed over only the anterior laryngeal branch. ZT also indicated the ILN or only the anterior laryngeal branch.

Conclusions: Zuckerkandl's tubercle indicated or passed over the ILN and the laryngeal branches. These findings suggest that an identifiable ZT could be used as a landmark to expose the ILN and the laryngeal branches.