title: Surgical approach to the thyroarytenoid branch of the inferior laryngeal nerve through the thyroid cartilage.
abstract: OBJECTIVE
  To describe the anatomical course of the intralaryngeal portion of the inferior laryngeal nerve (ILN) and to standardize the surgical access to its thyroarytenoid branch (TAb) through the thyroid cartilage.
  
  
  METHODS
  Under surgical microscopy, 33 adult human excised larynges were dissected, to expose the intralaryngeal portion of ILN. The point of entry of TAb, ILN's terminal branch, in the thyroarytenoid (TA) muscle was determined and correlated with thyroid cartilage dimensions.
  
  
  RESULTS
  After entering the larynx, the ILN consistently traveled between the thyroid cartilage and the lateral cricoarytenoid muscle in an anterior and slightly cranial course. The distance from the point of entry of the TAb in the TA muscle to the midline (TAb-H) and to the inferior border (TAb-V) of the thyroid cartilage differed according to gender. In females, mean distances of TAb-H and TAb-V were 20.5mm and 5.2mm and in males, 22.3mm and 5.9mm, respectively.
  
  
  CONCLUSIONS
  The intralaryngeal course of the inferior laryngeal nerve presents low variability and measures from landmarks in the thyroid cartilage help to estimate the point of entry of thyroarytenoid branch in thyroarytenoid muscle.
authors.affiliation: PhD, Supervisor, Residency Program in Otorhinolaryngology, Instituto de Medicina Integral Professor Fernando Figueira (IMIP), Recife-PE, Brazil. Scientific, intelectual, conception and design of the study; acquisition and interpretation of data; technical procedures; manuscript preparation and writing; final approval.
authors.forename: Fabiana Araújo
authors.initials: FA
authors.lastname: Sperandio
authors.affiliation: PhD, Assistant Professor, Postgraduate Program in Otorhinolaryngology, Division of Otorhinolaryngology, School of Medicine, Universidade de São Paulo (USP), Brazil. Scientific and design of the study, statistical analysis, manuscript preparation and writing, critical revision, final approval.
authors.forename: Rui
authors.initials: R
authors.lastname: Imamura
authors.affiliation: PhD, Associate Professor, Division of Otorhinolaryngology, School of Medicine, USP, Sao Paulo-SP, Brazil. Scientific, intelectual, conception and design of the study; manuscript preparation; critical revision; final approval.
authors.forename: Domingos Hiroshi
authors.initials: DH
authors.lastname: Tsuji
authors.affiliation: PhD, Associate Professor, Division of Otorhinolaryngology, School of Medicine, USP, Sao Paulo-SP, Brazil. Scientific, intelectual, conception and design of the study; manuscript preparation; critical revision; final approval.
authors.forename: Luiz Ubirajara
authors.initials: LU
authors.lastname: Sennes
mesh_terms: D000328:Adult; D004210:Dissection / Q000592:standards*; D005260:Female; D006801:Humans; D007821:Laryngeal Muscles / Q000294:innervation*; D008297:Male; D012009:Recurrent Laryngeal Nerve / Q000033:anatomy & histology / Q000601:surgery*; D012015:Reference Standards; D012737:Sex Factors; D013957:Thyroid Cartilage / Q000294:innervation*