title: Analysis of the position of the branches of the ulnar nerve in Guyon's canal using high-resolution MRI in positions adopted by cyclists.
abstract: OBJECTIVE
  To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon's canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists.
  
  
  METHODS
  Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH.
  
  
  RESULTS
  The mean distances between the SB (d s) and DP (d p) and HH were 2.4 and 0.6 mm, respectively. The d s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it.
  
  
  CONCLUSIONS
  This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon's canal syndrome in cyclists.
authors.affiliation: Guilloz Imaging Department, CHU Nancy - Hôpital Central, Rue du Maréchal de Lattre de Tassigny, 54000, Nancy, France. aym.rauch@gmail.com.
authors.forename: Aymeric
authors.initials: A
authors.lastname: Rauch
authors.affiliation: Guilloz Imaging Department, CHU Nancy - Hôpital Central, Rue du Maréchal de Lattre de Tassigny, 54000, Nancy, France.
authors.forename: Pedro Augusto Gondim
authors.initials: PA
authors.lastname: Teixeira
authors.affiliation: Guilloz Imaging Department, CHU Nancy - Hôpital Central, Rue du Maréchal de Lattre de Tassigny, 54000, Nancy, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Gillet
authors.affiliation: Anatomy Department, Faculty of Medicine, 9 Avenue de la Forêt de Haye, 54500, Vandoeuvre-Les-Nancy, France.
authors.forename: Manuela
authors.initials: M
authors.lastname: Perez
authors.affiliation: ESPRI-BioBase Unit, CHU Nancy - Hôpitaux de Brabois, Allée du Morvan, 54500, Vandoeuvre-Les-Nancy, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Clerc-Urmes
authors.affiliation: Guilloz Imaging Department, CHU Nancy - Hôpital Central, Rue du Maréchal de Lattre de Tassigny, 54000, Nancy, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Lombard
authors.affiliation: Guilloz Imaging Department, CHU Nancy - Hôpital Central, Rue du Maréchal de Lattre de Tassigny, 54000, Nancy, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Blum
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014459:Ulnar Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: Guyon’s canal; MRI; Ulnar nerve