title: How high do the subclavian arteries ascend into the neck? A population study using magnetic resonance imaging.
abstract: BACKGROUND
  The relationship between the larynx and the subclavian arteries was studied in a series of magnetic resonance images (MRIs) from 50 patients without neck pathology.
  
  
  METHODS
  The vertical distances of the excursion of the subclavian arteries into the neck was measured, as was the distance from the cricoid cartilage to the highest point of this excursion. Statistical analysis allows the probability of any given cricoid-subclavian distance occurring in the population to be estimated.
  
  
  RESULTS
  The mean (SD) excursion of the right subclavian artery above the clavicle was 10.4 (11.4) mm. The mean (SD) distance from the cricoid cartilage to the right subclavian artery was 30.6 (14.3) mm, and the data showed a high degree of variance. There was a linear relationship between neck length and cricoid-subclavian distance (r=0.58), which explained some of the variance in the latter, but there was also wide individual variance, which was independent of this regression.
  
  
  CONCLUSIONS
  When performing a percutaneous tracheostomy, a 'safe' distance between the incision site and subclavian artery cannot be assumed or reliably predicted from the neck length.
authors.affiliation: Neurointensive Care Unit and Department of Neuroradiology, Radcliffe Infirmary Woodstock Road, Oxford OX2 6HE, UK. andrew.farmery@nda.ox.ac.uk
authors.forename: A D
authors.initials: AD
authors.lastname: Farmery
authors.forename: D
authors.initials: D
authors.lastname: Shlugman
authors.forename: P
authors.initials: P
authors.lastname: Anslow
mesh_terms: D003413:Cricoid Cartilage / Q000033:anatomy & histology; D006801:Humans; D007830:Larynx / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging; D009333:Neck / Q000033:anatomy & histology*; D012016:Reference Values; D013348:Subclavian Artery / Q000033:anatomy & histology*; D014139:Tracheostomy