title: Morphology of the extensor carpi ulnaris groove and tendon.
abstract: OBJECTIVE
  Injury to the extensor carpi ulnaris (ECU) fascial supports on the distal ulna can result in ulnar-sided wrist pain, particularly when the tendon subluxates medially out of the fibroosseous groove with forearm rotation. To better understand the potential risk factors for injury and the indications for modifying the ECU groove, we have evaluated and quantified the morphology of the ECU groove and tendon.
  
  
  METHODS
  Axial plane magnetic resonance imaging of the wrist obtained for triangular fibrocartilage complex and intercarpal pathology in 60 patients were reviewed. Mean and standard error of the mean were calculated and unpaired Student t tests performed to compare groove width and depth, radius of curvature of the groove, carrying angle, and tendon-to-groove ratio.
  
  
  RESULTS
  There were 23 females (38%), and the mean patient age was 40 years (range, 17-71 y). The average ECU groove depth and standard error of the mean was 1.4 mm ± 0.1 mm. The radius of curvature for the ulnar ECU groove was found to be 7.0 mm ± 0.4 mm with a carrying angle of 143° ± 2°. In neutral forearm rotation, the average ratio of the width of the ECU tendon to groove was 0.7 ± 0.02. The data approximated a normal distribution. There were no statistically significant differences in these measurements between the triangular fibrocartilage complex and the intercarpal pathology subgroups.
  
  
  CONCLUSIONS
  Variability in the relationship of the ECU groove and tendon may combine to represent risk factors for tendinosis or tendon subluxation. There may be a more normal distribution of ECU groove morphology than previously recognized.
  
  
  CONCLUSIONS
  ECU injuries may require clinical imaging of the tendon and subsheath, in addition to potential surgical reconstruction and ulnar groove deepening. This report establishes the normative morphology and depth of the ECU groove and provides a comparative baseline when considering treatment modalities.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Orthopaedics & Sports Medicine, University of Washington Medical Center, Seattle, WA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Iorio
authors.affiliation: Division of Plastic and Reconstructive Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Orthopaedics & Sports Medicine, University of Washington Medical Center, Seattle, WA.
authors.forename: Ahmad F
authors.initials: AF
authors.lastname: Bayomy
authors.affiliation: Division of Plastic and Reconstructive Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Orthopaedics & Sports Medicine, University of Washington Medical Center, Seattle, WA. Electronic address: jihuang@uw.edu.
authors.forename: Jerry I
authors.initials: JI
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013708:Tendon Injuries / Q000473:pathology*; D013710:Tendons / Q000473:pathology*; D051478:Triangular Fibrocartilage / Q000473:pathology*; D014457:Ulna / Q000473:pathology*; D014954:Wrist Injuries / Q000473:pathology*; D014955:Wrist Joint / Q000473:pathology*
keywords: ECU groove; Extensor carpi ulnaris; distal ulna; ulnar wrist pain