title: Prevalence of C7 level anomalies at the C7 level: an important landmark for cervical nerve ultrasonography.
abstract: BACKGROUND
  Recently, various examination and intervention techniques using cervical nerve ultrasonography have been developed. The specific shapes of the C7 transverse process and vertebral artery in front of the C7 transverse process have become landmarks.
  
  
  OBJECTIVE
  To determine the prevalence of anomalies and anomalous vertebral artery entrances at the C7 transverse process.
  
  
  METHODS
  The records of patients who underwent plain or contrast-enhanced neck or cervical spine computed tomography (CT) were reviewed. The examinations were scored for the anomalous presence of anterior tubercles or cervical ribs as well as vertebral artery entrances in the C7 transverse process. The prevalence of anomalies was compared based on patient sex and age.
  
  
  RESULTS
  Evaluating the examinations from 2067 patients (1046 men; 1021 women), 1% of patients exhibited an anomalous presence of anterior tubercles, and 0.3% of patients displayed cervical ribs at the C7 transverse process. The prevalence of anomalies process was significantly higher in men aged less than 40 years than in older men (P < 0.001), whereas the prevalence was not higher in women aged less than 40 years than in older women. The prevalence of vertebral artery entry into the C7 transverse foramen was 0.6%.
  
  
  CONCLUSIONS
  Although an anomalous vertebral artery entry into the C7 transverse foramen was rare, the prevalence of an anomaly at the C7 transverse process was higher in men aged less than 40 years. Therefore, we recommend performing CT in younger men before cervical nerve ultrasonographic intervention to avoid misinterpretations at the cervical level.
authors.affiliation: Spine Center, Aichi Medical University Hospital, Nagakute, Aichi, Japan Department of Neurological Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan take7106@aichi-med-u.ac.jp.
authors.forename: Mikinobu
authors.initials: M
authors.lastname: Takeuchi
authors.affiliation: Department of Neurological Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Aoyama
authors.affiliation: Spine Center, Aichi Medical University Hospital, Nagakute, Aichi, Japan Department of Orthopedic Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Wakao
authors.affiliation: Department of Radiology, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Tawada
authors.affiliation: Spine Center, Aichi Medical University Hospital, Nagakute, Aichi, Japan Department of Orthopedic Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kamiya
authors.affiliation: Department of Neurological Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Osuka
authors.affiliation: Department of Neurological Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Matsuo
authors.affiliation: Spine Center, Aichi Medical University Hospital, Nagakute, Aichi, Japan Department of Neurological Surgery, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takayasu
mesh_terms: D017677:Age Distribution; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000294:innervation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D017678:Sex Distribution; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014711:Vertebral Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging*
keywords: Anomaly; head; neck; spine; ultrasound