title: A cadaveric study of the cervical nerve roots and spinal segments.
abstract: OBJECTIVE
  The purpose of this study was to anatomically measure the width of the cervical nerve root and spinal cord segment in addition to clarifying the anatomical characteristics of the cervical nerve root.
  
  
  METHODS
  We assessed 132 cervical nerve roots obtained from 11 cadavers. A total of 11 cervical spines from C3 to C8 were directly evaluated using digital calipers. The patients from whom the cadaveric specimens were obtained ranged from 79 to 90 years of age at the time of death. Four measurements were taken: the width at the entry of the spinal nerve in the vertebral foramen (WE), the maximum width of the spinal nerve (MW) and the length of the spinal segment on the ventral (LV) and dorsal rootlets (LD).
  
  
  RESULTS
  The mean values of the WE from C3 to C8 were 5.5, 5.6, 6.0, 5.8, 4.8 and 4.3 mm, respectively. The value of C8 was significantly smaller than that of C3, C4, C5 and C6. The mean values of the MW from C3 to C8 were 5.6, 6.0, 6.4, 6.7, 6.3 and 6.0 mm, respectively. The mean values of the LV from C3 to C8 were 12.1, 12.5, 12.6, 12.7, 11.8 and 10.6 mm, respectively. The value of C8 was significantly narrower than that of C4, C5 and C6. The mean values of the LD from C3 to C8 were 12.1, 13.3, 13.6, 12.2, 11.0 and 10.6 mm, respectively. The value of C8 was significantly narrower than that of C4 and C5.
  
  
  CONCLUSIONS
  We anatomically measured the width of cervical nerve roots and spinal segments. The spinal segment of C8 was significantly narrower than some of the roots located in the middle of the cervical spine, and this characteristic continued to the entry of the root in the vertebral foramen, although the difference disappeared at the maximum width point of the root.
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Kobayashi
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan. ihaku@gunma-u.ac.jp.
authors.forename: Haku
authors.initials: H
authors.lastname: Iizuka
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishinome
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Iizuka
authors.affiliation: Department of Anatomy, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yorifuji
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showa, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Takagishi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002102:Cadaver; D002574:Cervical Vertebrae / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D013126:Spinal Nerve Roots / Q000033:anatomy & histology*
keywords: Anatomy; Cervical nerve root; Spinal segment