title: An anatomical investigation of clock face landmarks around the glenoid for shoulder arthroscopy orientation.
abstract: BACKGROUND
  For shoulder arthroscopy, few anatomical landmarks are available and inexperienced surgeons tend to be adrift due to the limited visual field of the scope. The purpose of this study was to demonstrate the useful landmarks around the glenoid for accurate orientation, and also the safe distance to avoid suprascapular nerve injury during surgical procedures around the glenoid.
  
  
  METHODS
  In 15 human solution-fixed cadavers, a cross-section of the shoulder joint on the labrum surface was created. The positions of the principal anatomical structures surrounding the glenoid were marked on the labrum and measured using our clock face indication system. In 9 shoulders the distances from the labral surface to the spinoglenoid notch were recorded. As an indicator of the scapula size, the distances between the superior and inferior angles of the scapula were also measured.
  
  
  RESULTS
  The average landmark positions in the right shoulder were as follows: center of the attachment of the long tendon 11:59, anterior edge of the supraspinatus 11:59, posterior edge of the base of the coracoid process 12:13, superior edge of the subscapularis 1:03, anterior edge of the base of the coracoid process 1:25, inferior edge of the subscapularis 5:27, inferior edge of the teres minor 6:21, border of the infraspinatus and teres minor 7:43, center of the scapula spine 10:06, border of the supra and infraspinatus 10:27. The average distance from the labral surface to the spinoglenoid notch was 23.17 mm, and that from the superior to inferior angle was 144.93 mm. The Pearson correlation coefficient for these distances was 0.007.
  
  
  CONCLUSIONS
  The locations of anatomical landmarks surrounding the glenoid were reliably demonstrated using our clock face indication system. The expected distance from the labral surface to the suprascapular nerve was approximately 23 mm, irrespective of the size of the scapula.
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan. Electronic address: arairyuzo@gmail.com.
authors: Ryuzo
authors: R
authors: Arai
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Hideto
authors: H
authors: Harada
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Hiroyuki
authors: H
authors: Tsukiyama
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Yoshimitsu
authors: Y
authors: Takahashi
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Masahiko
authors: M
authors: Kobayashi
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Takahiko
authors: T
authors: Saji
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto City, Kyoto Pref., 606-8507, Japan.
authors: Shuichi
authors: S
authors: Matsuda
mesh_terms: D059925:Anatomic Landmarks / Q000601:surgery*; D001182:Arthroscopy / Q000379:methods*; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000601:surgery*