title: Evaluation of the acromiohumeral distance by means of magnetic resonance imaging umerus.
abstract: OBJECTIVE
  To demonstrate the relationship between the size, degree of retraction and topography of rotator cuff injuries and the degree of rise of the humeral head, and to evaluate the influence of gravity, using magnetic resonance imaging (MRI).
  
  
  METHODS
  We evaluated 181 shoulder MRIs from 160 patients aged over 45 years, between November 2013 and July 2014. The patients were divided into two groups: one control (no lesion or partial damage to the rotator cuff); and the other with complete tears of the rotator cuff. We measured the acromiohumeral distance in the sagittal plane, and established the shortest distance between the apex of the head and the acromion.
  
  
  RESULTS
  In this study, 96 examinations on female patients (53.04%) and 58 on male patients (46.96%) were evaluated. The mean age was 63.27 years: in the control group, 61.46; and in the group with injuries, 65.19. From analysis on the measurements of the subacromial space, we observed significantly higher values in the control group (7.71 mm) than in the group with injuries (6.99). In comparing the control group with some specific subgroup, i.e. posterosuperior (6.77), anteroposterior-superior (4.16) and retraction Patte III (5.01), we confirmed the importance of topography and degree of retraction in relation to the rise of the humeral head.
  
  
  CONCLUSIONS
  The rise of the humeral head was directly related to the size, degree of retraction and topography of the rotator cuff injuries, with greater degrees of rise in cases of superior and posterior lesions and anteroposterior-superior (massive) lesions. The assessment using MRI was not influenced by the force of gravity.
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: Flávio
authors.initials: F
authors.lastname: de Oliveira França
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: André Couto
authors.initials: AC
authors.lastname: Godinho
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: Elísio José Salgado
authors.initials: EJ
authors.lastname: Ribeiro
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Falster
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: Lucas Emanuel Gava
authors.initials: LE
authors.lastname: Búrigo
authors.affiliation: Hospital Ortopédico BH, Belo Horizonte, MG, Brazil.
authors.forename: Rafael Berenstein
authors.initials: RB
authors.lastname: Nunes
keywords: Acromion; Humerus; Magnetic resonance imaging; Rotator cuff