title: An anatomic and morphometric study of C2 nerve root ganglion and its corresponding foramen.
abstract: METHODS
  Exposing and measuring the dorsal root ganglion of the second cervical spinal nerve (C2 ganglion) and the second intervertebral space, which is present between posterior arch of atlas (APA) and lamina of axis (LA).
  
  
  OBJECTIVE
  This study aims to investigate the shape, size, and relation of the C2 ganglion with the adjacent structures that limits the corresponding intervertebral space and the alterations of relation between C2 ganglion and APA and between C2 ganglion and LA with the movements of the head bilaterally.
  
  
  BACKGROUND
  In previous studies, the position and the heights of the C2 ganglion have been described. But the shape of the C2 ganglion and its relation to APA and LA by the movement of the head had not been considered previously.
  
  
  METHODS
  Upper cervical spines of 20 cadavers were dissected posteriorly. The muscles attaching to the atlas and axis were resected to ease the head movements. The heights of the C2 ganglion and space were measured in anatomic position and in hyperextension with opposite rotation position of the head. Originally in this study, plastic dough casts were used to obtain reliable outcomes.
  
  
  RESULTS
  The shape of the ganglions was defined in three types: 70% were oval, 20% were spindle-like, and 10% were spherical. The height of the C2 ganglion was 4.97 +/- 0.92 mm on the right side and 4.6 +/- 0.84 mm on the left side. The height of the intervertebral space in anatomic position and in hyperextension with rotation to the opposite position of the head were, respectively, 9.74 +/- 1.77 mm and 7.48 +/- 1.44 mm on the right side and 9.64 +/- 1.47 mm and 7.12 +/- 0.96 mm on the left side. There was no bone contact or impact to the ganglion in each position of the head.
  
  
  CONCLUSIONS
  The C2 ganglions are confident in their place between APA and LA. No bone contact to the C2 ganglion was detected in either normal limited or in forced head motions.
authors.affiliation: Department of Anatomy of Medical Faculty of Ege University, Izmir, Turkey. obilge@med.ege.edu.tr
authors.forename: Okan
authors.initials: O
authors.lastname: Bilge
mesh_terms: D000328:Adult; D000886:Anthropometry; D001368:Axis, Cervical Vertebra / Q000033:anatomy & histology*; D001270:Cervical Atlas / Q000033:anatomy & histology*; D005727:Ganglia, Spinal / Q000033:anatomy & histology*; D019416:Head Movements; D006801:Humans; D012016:Reference Values; D013126:Spinal Nerve Roots / Q000033:anatomy & histology*