title: An anatomical study of the subcoracoid space.
abstract: OBJECTIVE
  To evaluate the amplitude of the subcoracoid space under maximum internal and external rotations of the humeral head and measure the distance between the apex of the coracoid process and the following anatomical structures: (a) point of entry of the musculocutaneous nerve and its branches into the coracobrachial muscles and into the short head of the biceps brachii muscle; (b) acromial artery; (c) lesser tubercle of the humerus.
  
  
  METHODS
  Thirty shoulders of fresh cadavers, without any kind of shoulder pathology, (9 males and 6 females) were dissected, and the distances (in mm) were measured between the anatomical structures defined above and the apex of the coracoid process.
  
  
  RESULTS
  The mean distance between the apex of the coracoid process and the musculocutaneous nerve was 49.2 mm (in all specimens a proximal branch of the nerve was identified 34.2 mm away from the apex of the coracoid process), which was not significantly different between the sexes or body sides; the mean distance between the apex of the coracoid process and the acromial artery was 12.4 mm, which was not significantly different between the sexes or body sides; the mean distance between the apex of the coracoid process and the lesser tubercle of the humerus, with the humeral head under internal rotation, was 10.6 mm in men and 8.6 mm in women, values that were significantly different between the sexes.
  
  
  CONCLUSIONS
  In women, the smaller distance between the apex of the coracoid process and the lesser tubercle of the humerus in the arm internal rotation suggests a higher chance of impingement between those bone structures among the female sex.
authors.affiliation: Shoulder and Elbow Group and Arthroscopy, Laboratory of Department of Orthopedics, Faculty of Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil. aafneto@terra.com.br
authors.forename: Arnaldo Amado
authors.initials: AA
authors.lastname: Ferreira Neto
authors.forename: Adriano Marques de
authors.initials: AM
authors.lastname: Almeida
authors.forename: Renzo
authors.initials: R
authors.lastname: Maiorino
authors.forename: Américo
authors.initials: A
authors.lastname: Zoppi Filho
authors.forename: Eduardo
authors.initials: E
authors.lastname: Benegas
mesh_terms: D000174:Acromion / Q000098:blood supply / Q000294:innervation; D002102:Cadaver; D005260:Female; D006801:Humans; D006811:Humerus / Q000033:anatomy & histology* / Q000294:innervation; D008297:Male; D009138:Musculocutaneous Nerve / Q000033:anatomy & histology*; D016059:Range of Motion, Articular; D012399:Rotation; D012540:Scapula / Q000033:anatomy & histology* / Q000294:innervation; D017678:Sex Distribution; D012737:Sex Factors; D019534:Shoulder Impingement Syndrome / Q000473:pathology; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000294:innervation