title: Anatomical variations of the superior thyroid and superior laryngeal arteries.
abstract: BACKGROUND
  There are known to be variations in the origins of the superior thyroid artery (STA), an important surgical landmark, and 1 of its branches, the superior laryngeal artery (SLA).
  
  
  METHODS
  Three hundred thirty human embalmed heminecks were dissected. The results of previous studies were reviewed, and a meta-analysis is presented.
  
  
  RESULTS
  Four different origins for the STA were found. The most frequent was type I, from the carotid bifurcation (49%). Four different origins were also found for the SLA being the most frequent the type I in which the artery arose from STA (78%). The mean external diameters of STA and SLA were 0.26 and 0.20 cm, respectively, with no statistically significant differences by side or sex.
  
  
  CONCLUSIONS
  Variations in the origin of STA and SLA from the carotid arterial tree and the similarity of their diameters mean that there is a significant possibility of their misidentified during surgery.
authors.affiliation: Department of Human Anatomy and Embryology, I. School of Medicine, Complutense University of Madrid, Madrid, Spain. tvazquez@med.ucm.es
authors.forename: Teresa
authors.initials: T
authors.lastname: Vázquez
authors.forename: Rosana
authors.initials: R
authors.lastname: Cobiella
authors.forename: Eva
authors.initials: E
authors.lastname: Maranillo
authors.forename: Francisco Jose
authors.initials: FJ
authors.lastname: Valderrama
authors.forename: Stephen
authors.initials: S
authors.lastname: McHanwell
authors.forename: Ian
authors.initials: I
authors.lastname: Parkin
authors.forename: Jose Ramon
authors.initials: JR
authors.lastname: Sañudo