title: Relationship of the Medial Clavicular Head to the Manubrium in Normal and Symptomatic Degenerated Sternoclavicular Joints.
abstract: BACKGROUND
  Clavicular prominence is common in patients with symptomatic degenerative sternoclavicular arthritis. It is unclear if this is caused by enlargement or subluxation of the clavicle. The aim of this report is to describe a reproducible measurement technique to evaluate the relationship of the medial clavicular head to the manubrium.
  
  
  METHODS
  One hundred normal sternoclavicular joints, twenty-five sternoclavicular joints with symptomatic degenerative arthritis, and twenty-five non-symptomatic sternoclavicular joints on the contralateral side were studied with three-dimensional (3D) reconstruction with use of computer modeling. The greatest width (anterior-posterior distance) and height (superior-inferior distance) of the clavicle in the sagittal plane were measured, and the positions of the anterior and superior borders of the medial clavicle and their distances to the frontal and axial planes, respectively, were evaluated. The ratio of the anterior-posterior distance to the anterior-frontal plane distance was measured to evaluate the anterior-posterior position of the clavicle and the ratio of the superior-inferior distance to the superior-axial plane distance was measured to evaluate its superoinferior position. If the ratio was not in the 95% normal range, the clavicle was defined as subluxated. The reproducibility of this technique was evaluated on the basis of the interobserver and intraobserver reliability.
  
  
  RESULTS
  This technique showed good interobserver and intraobserver reliability. The mean anterior-posterior and superior-inferior distances were significantly larger in association with symptomatic sternoclavicular arthritis than in the normal sternoclavicular joints (p < 0001). The clavicle was subluxated anteriorly in twenty-two of the twenty-five cases of symptomatic sternoclavicular arthritis, but it was not subluxated superiorly.
  
  
  CONCLUSIONS
  The medial clavicular head in patients with degenerative sternoclavicular arthritis is significantly larger than it is in the normal population, and it is usually subluxated anteriorly.
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail address for A. Van Tongel: Alexander.vantongel@uzgent.be.
authors.forename: Alexander
authors.initials: A
authors.lastname: Van Tongel
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail address for A. Van Tongel: Alexander.vantongel@uzgent.be.
authors.forename: Jens
authors.initials: J
authors.lastname: Valcke
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail address for A. Van Tongel: Alexander.vantongel@uzgent.be.
authors.forename: Iwein
authors.initials: I
authors.lastname: Piepers
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail address for A. Van Tongel: Alexander.vantongel@uzgent.be.
authors.forename: Thomas
authors.initials: T
authors.lastname: Verschueren
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail address for A. Van Tongel: Alexander.vantongel@uzgent.be.
authors.forename: Lieven
authors.initials: L
authors.lastname: De Wilde
mesh_terms: D000328:Adult; D002968:Clavicle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008371:Manubrium / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology*; D015203:Reproducibility of Results; D013247:Sternoclavicular Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed