title: Magnetic resonance imaging evaluation of normal glenoid length and width: an anatomic study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the measured dimensions of the normal glenoid on sagittal magnetic resonance (MR) imaging to determine whether a fixed ratio of glenoid length and width can be determined.
  
  
  METHODS
  MR images of 90 glenoids in 84 patients were analyzed. The mean age was 54.8 years, with 44 male and 40 female patients. Glenoid length and width at the widest dimension were measured and recorded by 3 independent examiners. The ratio of length to width and the ratio of the length of the superior pole at the widest point to the total length were calculated. Intraclass correlation coefficients, Spearman and Pearson correlations, regression analysis with cross validation, and coefficients of variation were calculated.
  
  
  RESULTS
  The mean glenoid length was 37.5 ± 3.8 mm, whereas the mean width was 24.4 ± 2.9 mm. The mean ratio of length to width was 1.55 ± 0.1, whereas the mean ratio of the distance from the superior pole to the widest point to the total glenoid length was 0.64 ± 0.03. The calculated ratios were less variable than the absolute length and width. Cross validation of length for width showed a 95% prediction band width of 4.48 mm, with an average absolute error of prediction of 1.46 mm, and was equally specific when separated by gender. The width was equal to 0.65 times the length.
  
  
  CONCLUSIONS
  Measurement of glenoid length and width using MR imaging results in a consistent ratio of length to width independent of patient age and gender, where the width was equal to 0.65 times the length at a point two-thirds along the inferosuperior axis.
  
  
  METHODS
  Level IV, case series.
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Brett A
authors.initials: BA
authors.lastname: Lenart
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Ryan
authors.initials: R
authors.lastname: Freedman
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Van Thiel
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Aman
authors.initials: A
authors.lastname: Dhawan
authors.affiliation: Department of General Surgery, William Beaumont Hospital, Royal Oak, Michigan, U.S.A.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: McGill
authors.affiliation: Department of Preventative Medicine, Graduate College, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Sanjib
authors.initials: S
authors.lastname: Basu
authors.affiliation: Department of Radiology, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: John R
authors.initials: JR
authors.lastname: Meyer
authors.affiliation: Department of Orthopaedic Surgery, Naval Medical Center San Diego, San Diego, California, U.S.A.
authors.forename: Cdr Matthew T
authors.initials: CM
authors.lastname: Provencher
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Romeo
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.. Electronic address: nverma@rushortho.com.
authors.forename: Nikhil N
authors.initials: NN
authors.lastname: Verma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012540:Scapula / Q000033:anatomy & histology*; D055815:Young Adult