Aims: The paper draws attention to the importance of rare, but important anatomical variety of nervus laryngeus recurrens, s.c. nervus laryngeus non-recurrens, for making thyroidectomy safely. Possible differences in the course of the nerve and the way of preparing the gland for minimizing the peroperation damage are presented. Patients: Three cases out of 1,200 operations on thyroid gland (0.25%) had the anatomical deviation described Results: The nerve was saved from peroperation damage in two patients with nervus laryngeus recurrens. The third patient with this deviation ended up with permanent unilateral paralysis of the nerve, which indicated erroneous evaluation of nerve branches. Conclusions: Possible occurrence of rare varieties of nervus laryngeus recurrens point out necessary routine search and careful dissection during thyroidectomy. The diagnosis of nervus laryngeus non-recurrens is not possible in most cases. This contribution draws attention to basic operation procedures, which protect not only nervus laryngeus recurrens in its typical position, but also its varieties such as nervus laryngeus non-recurrens.

        Key words: nervus laryngeus non-recurrens (NLNR) – dysphagia lusoria – arteria lusoria – thyroidectomy