title: Anatomic landmarks for arthroscopic suprascapular nerve decompression.
abstract: OBJECTIVE
  Arthroscopic suprascapular nerve (SSN) decompression has become a more frequently utilized procedure in the treatment of SSN entrapment and has gained popularity over recent years. Despite increasing technical notes and outcomes information regarding this technique, there remains a paucity of data with respect to clear anatomic guidelines for teaching this procedure. The purpose of this study was to provide guidelines that are visible arthroscopically and palpable externally to allow safer and more efficient surgery for arthroscopic decompression by analysing the superior scapular anatomy with respect to local landmarks.
  
  
  METHODS
  A cadaveric study was used to examine neurovascular structural measurements obtained in twelve cadavera with 23 usable shoulders. Arthroscopic dissection of the pertinent anatomy as determined by previously described approaches was followed by meticulous open regional dissection and measurements of the local landmarks.
  
  
  RESULTS
  Measurements of the pertinent arthroscopic anatomy with respect to local landmarks of the superior shoulder were recorded in 23 shoulders and are included herein. Measurements taken arthroscopically on 22 shoulders revealed that the lateral insertion of the transverse suprascapular ligament to the acromioclavicular joint was 3.6 cm (SD 0.5 cm). One of the anatomic measurements on open dissection had a significant correlation with our subject's demographics and was found between cadaveric height and the linear distance from the lateral acromion to the suprascapular notch (mean distance = 66.53 ± 5.30 mm; Pearson's correlation = 0.739; p = 0.006).
  
  
  CONCLUSIONS
  This cadaveric study describes meaningful landmarks and their measurements, which are identifiable arthroscopically and enable safer surgery in this area. Using these numbers, surgeons can know that it is safe to bluntly dissect to 2.5 cm medial to the acromioclavicular joint (and 5 cm medial to the palpable lateral acromion) before dissection is likely to encounter the SSN or artery. This knowledge will allow surgeons to learn this surgical technique, and for surgical educators to safely teach dissection and release in this uncommonly accessed anatomic region.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, 2450 Riverside Ave S #R200, Minneapolis, MN, 55454, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Knudsen
authors.affiliation: , Minneapolis, MN, USA.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Hibbard
authors.affiliation: , Minneapolis, MN, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Nuckley
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, 2450 Riverside Ave S #R200, Minneapolis, MN, 55454, USA. brama011@umn.edu.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Braman
mesh_terms: D000173:Acromioclavicular Joint / Q000033:anatomy & histology*; D000174:Acromion / Q000033:anatomy & histology; D059925:Anatomic Landmarks; D001182:Arthroscopy / Q000379:methods*; D001917:Brachial Plexus / Q000033:anatomy & histology*; D002102:Cadaver; D019299:Decompression, Surgical / Q000379:methods*; D004210:Dissection; D006801:Humans; D008022:Ligaments / Q000033:anatomy & histology; D009408:Nerve Compression Syndromes / Q000601:surgery*; D017006:Rotator Cuff / Q000033:anatomy & histology*; D012540:Scapula / Q000033:anatomy & histology; D012782:Shoulder / Q000033:anatomy & histology; D012785:Shoulder Joint / Q000033:anatomy & histology*
keywords: Arthroscopy; Cadaver; Decompression; Landmarks; Subacromial; Suprascapular nerve