title: T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons.
abstract: OBJECTIVE
  We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual.
  
  
  METHODS
  We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb's angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs.
  
  
  RESULTS
  The relationships between each value were analyzed and we concluded that Cobb's angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases.
  
  
  CONCLUSIONS
  We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.
authors.affiliation: Department of Neurosurgery, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Chul Bum
authors.initials: CB
authors.lastname: Cho
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Song
authors.forename: Seok Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Yoon
authors.initials: Y
authors.lastname: Ha
authors.forename: Jae Keun
authors.initials: JK
authors.lastname: Oh
keywords: Cervical sagittal alignment; Cobb's angle C2-7; T1 slope