title: Anatomical variations of the common carotid artery bifurcation.
abstract: BACKGROUND
  The correlation of the common carotid artery (CCA) bifurcation and its surrounding structures is poorly described. The aim of this study was to describe the anatomy of the CCA bifurcation relative to its surrounding structures.
  
  
  METHODS
  We dissected a total of 67 carotid specimens from 36 embalmed cadavers. CCA bifurcation occurred at the superior border of thyroid cartilage in 39% and at the body of hyoid bone in 40% of specimens.
  
  
  RESULTS
  The superior thyroid artery arose more commonly from the CCA (52.3%) than the external carotid artery (46.2%). The vagus nerve was posterior to the carotid bifurcation in 40 (60%), posterior-lateral in 24 (36%), posterior-medial in 2 (3%) and anterior-lateral in 1 specimen (1.5%). The hypoglossal nerve was closer to the CCA bifurcation when the CCA bifurcated at the level of the hyoid bone than when it bifurcated at the superior border of the thyroid cartilage (P < 0.05). The correlation of the common facial vein and the carotid artery was highly variable.
  
  
  CONCLUSIONS
  The presence of a high CCA bifurcation should caution surgeons that the hypoglossal nerve lies in closer proximity and is more vulnerable. Preoperatively documenting the level of the CCA bifurcation may be helpful in identifying those patients at increased risk of iatrogenic injury.
authors.affiliation: Department of General Surgery, Middlemore Hospital, Auckland, New Zealand. loalbert21@yahoo.co.uk
authors.forename: Albert
authors.initials: A
authors.lastname: Lo
authors.forename: Michael
authors.initials: M
authors.lastname: Oehley
authors.forename: Adam
authors.initials: A
authors.lastname: Bartlett
authors.forename: Dave
authors.initials: D
authors.lastname: Adams
authors.forename: Phil
authors.initials: P
authors.lastname: Blyth
authors.forename: Saad
authors.initials: S
authors.lastname: Al-Ali
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002342:Carotid Artery, External / Q000033:anatomy & histology* / Q000294:innervation; D002343:Carotid Artery, Internal / Q000033:anatomy & histology* / Q000294:innervation; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D014630:Vagus Nerve / Q000033:anatomy & histology