title: Vulnerability of the sympathetic trunk during the anterior approach to the lower cervical spine.
abstract: METHODS
  Anatomic dissection and measurements of the cervical sympathetic trunk relative to the medial border of the longus colli muscle and lateral angulation of the sympathetic trunk relative to the midline on both sides were performed.
  
  
  OBJECTIVE
  To determine the course and location of the sympathetic trunk quantitatively and relate this to the vulnerability of the sympathetic trunk during the anterior approach to the lower cervical spine.
  
  
  BACKGROUND
  The sympathetic trunk is sometimes damaged during the anterior approach to lower cervical spine, resulting in Horner's syndrome with its associated ptosis, meiosis, and anhydrosis. No quantitative regional anatomy describing the course and location of the sympathetic trunk and its relation to the longus colli muscle is available in the literature.
  
  
  METHODS
  In this study, 28 adult cadavers were used for dissection and measurements of the sympathetic trunk. The distance between the sympathetic trunk and the medial borders of the longus colli muscle at C6 and the angle of the sympathetic trunk with respect to the midline were determined bilaterally. The distance between the medial borders of the longus colli muscle from C3 to C6 and the angle between the medial borders of the longus colli muscle also were measured.
  
  
  RESULTS
  The sympathetic trunk runs in a superior and lateral direction, with an average angle of 10.4 +/- 3.8 degrees relative to the midline. The average distance between the sympathetic trunk and the medial border of the longus colli muscle is 10.6 +/- 2.6 mm. The average diameter of the sympathetic trunk at C6 is 2.7 +/- 0.6 mm. The length and width of the middle cervical ganglion were 9.7 +/- 2.1 mm and 5.2 +/- 1.3 mm, respectively. The distance between the medial borders of the longus colli muscle was 7.9 +/- 2.2 mm at C3, 10.1 +/- 3.1 mm at C4, 12.3 +/- 3.1 mm at C5, and 13.8 +/- 2.2 mm at C6, and the angle between the medial borders of the longus colli muscle was 12.5 +/- 4. 7 degrees.
  
  
  CONCLUSIONS
  The sympathetic trunk may be more vulnerable to damage during anterior lower cervical spine procedures because it is situated closer to the medial border of the the longus colli muscle at C6 than at C3. The longus colli muscles diverge laterally, whereas the sympathetic trunks converge medially at C6. As the transverse foramen or uncovertebral joint is exposed with dissection or transverse severance of the longus colli muscle at the lower cervical levels, the sympathetic trunk should be identified and protected.
authors.affiliation: Departments of Orthopaedic Surgery, Medical College of Ohio, Toledo 43614, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Ebraheim
authors.forename: J
authors.initials: J
authors.lastname: Lu
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: B E
authors.initials: BE
authors.lastname: Heck
authors.forename: R A
authors.initials: RA
authors.lastname: Yeasting
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002574:Cervical Vertebrae / Q000294:innervation* / Q000601:surgery*; D005260:Female; D006732:Horner Syndrome / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000601:surgery; D011183:Postoperative Complications / Q000517:prevention & control; D013514:Surgical Procedures, Operative / Q000379:methods; D013564:Sympathetic Nervous System / Q000033:anatomy & histology* / Q000601:surgery*