title: Anatomic variations in the first extensor compartment of the wrist: accuracy of US.
abstract: OBJECTIVE
  To evaluate the accuracy of ultrasonography (US) in determining the anatomic variations in the first extensor compartment of the wrist.
  
  
  METHODS
  Approval from the anatomic donations department was obtained. The first extensor compartment of the wrist of 40 nonembalmed cadaveric forearms (15 male and 25 female; age range at death, 65-100 years) were assessed at US by two observers for the presence or absence of a vertical septum, the presence or absence of an osseous ridge with a double groove in the bony floor, and whether there were single or multiple slips of the abductor pollicis longus and the extensor pollicis brevis tendons. These findings were also evaluated at dissection.
  
  
  RESULTS
  The accuracies of US in depicting a septum and an osseous ridge with a double groove were respectively 95% (95% confidence interval [CI]: 83%, 99%) and 100% (95% CI: 91%, 100%). At dissection, a septum was invariably associated with the presence of an osseous ridge. The accuracies of US in depicting multiple tendon slips of the abductor pollicis longus and the extensor pollicis brevis were respectively 80% (95% CI: 64%, 91%) and 97% (95% CI: 86%, 100%).
  
  
  CONCLUSIONS
  US was highly accurate in depicting anatomic variations in the first extensor compartment. US detection of an osseous ridge was an indirect sign of the presence of a septum dividing the first extensor compartment into two subcompartments.
authors.affiliation: Department of Radiology, Université Paris Descartes, Assistance Publique des Hôpitaux de Paris, Hôpital Hôtel Dieu, 1 Place du Parvis Notre Dame, 75004 Paris, France. rousset.pas@voila.fr
authors.forename: Pascal
authors.initials: P
authors.lastname: Rousset
authors.forename: Valérie
authors.initials: V
authors.lastname: Vuillemin-Bodaghi
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Laredo
authors.forename: Caroline
authors.initials: C
authors.lastname: Parlier-Cuau
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013710:Tendons / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D014955:Wrist Joint / Q000000981:diagnostic imaging*