title: Redefining the proximal ulna anatomy.
abstract: OBJECTIVE
  Complex fractures of the olecranon have always been a difficult condition for treatment. Successful reconstruction depends on restoration of the anatomic contributors to stability. The purpose of this study was to define the proximal ulna anatomy in detail with respect to fracture fixation and arthroscopy.
  
  
  METHODS
  In 50 normal adult ulnae (26 left, 24 right); posterior olecranon height (POH), olecranon width (OW), trochlear notch width (TW), the distances between the olecranon and the trochlear notch on radial and ulnar sides (RTH, UTH), and proximal ulnar angulations were measured with a ruler and a digital goniometer.
  
  
  RESULTS
  The average POH was 24.6 mm, OW was 23.1 mm, TW was 22.3 mm, RTH was 16.2 mm, and UTH was 15.8 mm. The mean value for proximal ulna torsion angle (PUTA) was found 11.1°. The mean varus angulation was 9.3°. The average articular angle was 27.7° and proximal ulnar dorsal angulation (PUDA) was 8°.
  
  
  CONCLUSIONS
  The unique bony architecture of the proximal ulna presents particular difficulties for the implants used in fracture fixation and arthroplasty of the elbow. Knowing the detailed anatomy of the variations of proximal ulna will guide the surgeon to obtain a more reliable length of the olecranon and to offer a safe place for Kirschner wire replacement concerning humero-ulnar joint functionality. In this study, PUTA was also defined. The angle determines the rotation of the proximal ulna and it has a great importance for the movements of the joint. The measured angulations will help the surgeon to design the proper prosthesis for the maintenance of the functions of the elbow joint.
authors.affiliation: Department of Anatomy, Faculty of Medicine, Hacettepe University, Ankara, Turkey, crngnc5er@gmail.com.
authors.forename: Ceren Günenç
authors.initials: CG
authors.lastname: Beşer
authors.forename: Deniz
authors.initials: D
authors.lastname: Demiryürek
authors.forename: Hakan
authors.initials: H
authors.lastname: Özsoy
authors.forename: Burcu
authors.initials: B
authors.lastname: Erçakmak
authors.forename: Mutlu
authors.initials: M
authors.lastname: Hayran
authors.forename: Onur
authors.initials: O
authors.lastname: Kızılay
authors.forename: Arzu
authors.initials: A
authors.lastname: Özsoy
mesh_terms: D001837:Body Weights and Measures / Q000379:methods; D002102:Cadaver; D006801:Humans; D014457:Ulna / Q000033:anatomy & histology*