title: Estimation of base of middle phalanx size using anatomical landmarks.
abstract: OBJECTIVE
  To determine whether there is a measurable and reproducible relationship between the articular surface size of the middle phalanx base and the size of the middle phalanx head and proximal phalanx length of the same finger.
  
  
  METHODS
  Size of the articular surface of the middle phalanx base, size of the middle phalanx head, and proximal phalanx length were measured in 84 lateral radiographs by 3 observers.
  
  
  RESULTS
  The ratio of articular surface size of the middle phalanx base to the proximal phalanx length of the same finger was 0.17. The ratio of articular surface size of the middle phalanx base to the size of the middle phalanx head of the same finger was 1.34. The intraclass correlation (ICC) among 3 raters was 0.99 for proximal phalanx length and 0.88 for size of the middle phalanx head.
  
  
  CONCLUSIONS
  Knowledge of this relationship and ratios allow for accurate estimation of the percentage of articular surface involvement in a fracture of the middle phalanx base. The ICC was highest for measuring proximal phalanx length, making it the most reliable measurement for estimation of the articular surface size.
  
  
  CONCLUSIONS
  This quantitative estimate may be useful for clinical research and is applicable to patient care.
authors.affiliation: Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Boston, MA.
authors.forename: Stein J
authors.initials: SJ
authors.lastname: Janssen
authors.affiliation: Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Boston, MA.
authors.forename: Teun
authors.initials: T
authors.lastname: Teunis
authors.affiliation: Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Boston, MA.
authors.forename: Dirk P
authors.initials: DP
authors.lastname: ter Meulen
authors.affiliation: Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Boston, MA.
authors.forename: Michiel G J S
authors.initials: MG
authors.lastname: Hageman
authors.affiliation: Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Boston, MA. Electronic address: dring@mgh.harvard.edu.
authors.forename: David
authors.initials: D
authors.lastname: Ring
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049628:Body Size; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging*; D050278:Finger Phalanges / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D055815:Young Adult
keywords: Anatomical landmarks; articular surface size; fracture; middle phalanx; proximal interphalangeal joint