title: Contribution of cartilage to size and shape of radial head circumference: magnetic resonance imaging analysis of 78 elbows.
abstract: BACKGROUND
  The aims of our study were to quantify cartilage thickness at the minimum and maximum diameters of the radial head circumference and to investigate its influence on the size and shape of the proximal radius.
  
  
  METHODS
  We analyzed high-definition magnetic resonance imaging scans of 78 healthy elbows in 19 men and 20 women, with a mean age of 28 (21-32) years. All measurements were estimated in the axial plane just distal to the fovea radialis. Maximum and minimum bone diameters, maximum and minimum total diameters (including cartilage thickness), and cartilage thickness were calculated. Cartilage thickness was measured at 4 different points: (1) at the articular side of the maximum diameter (point A), (2) at the nonarticular side of the maximum diameter (point B), (3) at the medial side of the minimum diameter (point C), and (4) at the lateral side of the minimum diameter (point D). Pearson correlation and t test were used for the statistical analysis.
  
  
  RESULTS
  Mean maximum and minimum bone diameters and maximum and minimum total diameters were 22.2, 21.5, 24.0, and 23.2 mm, respectively. All differences between diameters were statistically significant. Mean cartilage thickness at points A, C, and D was 1.7, 0.8, and 0.8 mm, respectively. No measurable cartilage thickness was found at point B. No significant correlation was found between bone diameters and cartilage thickness.
  
  
  CONCLUSIONS
  Cartilage surface significantly increases and modifies the size and shape of the radial head. The observation that cartilage thickness varies between subjects and does not correlate with bone parameters suggests that the diameters of the radial head cannot be inferred from indirect measurements of dry bones or radiographs.
authors.affiliation: Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy. Electronic address: giannicola.giuseppe@gmail.com.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giannicola
authors.affiliation: Department of Radiology, Campus Bio-medico University of Rome, Rome, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Sedati
authors.affiliation: Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Polimanti
authors.affiliation: Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cinotti
authors.affiliation: Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bullitta
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D004551:Elbow Joint / Q000033:anatomy & histology*; D004838:Epiphyses / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011884:Radius / Q000033:anatomy & histology*; D055815:Young Adult
keywords: MRI study; Radial head; cartilage thickness; elbow joint anatomy; proximal radius; shape of radial head; size of radial head