[The nonrecurrent inferior laryngeal nerve. Apropos of 19 cases including 2 on the left side].

Nineteen cases of non-recurrent inferior laryngeal nerve were identified during 3791 cervicotomies for thyroid or parathyroid excision over the last 7 years, the nervous anomaly being of vascular anomaly origin in all cases. Predisposing factors for its onset during aortic arch development are discussed, together with possible symptomatology and means for preoperative diagnosis. Frequency in the cases reported was 0,54% from 3098 dissections on the right and 0,07% from 2846 dissections on the left. Although rare on the right and exceptional on the left, an aberrant non-recurrent pathway for the inferior laryngeal nerve represents a major, surgical risk during thyroid or parathyroid excision.