Direct 3-dimensional measurement of scapular kinematics during dynamic movements in vivo

J Shoulder Elbow Surg. May-Jun 2001;10(3):269-77. doi: 10.1067/mse.2001.112954.

Abstract

The purpose of this study was to describe 3-dimensional scapular motion patterns during dynamic shoulder movements with the use of a direct technique. Direct measurement of active scapular motion was accomplished by insertion of 2 1.6-mm bone pins into the spine of the scapula in 8 healthy volunteers (5 men, 3 women). A small, 3-dimensional motion sensor was rigidly fixed to the scapular pins. Sensors were also attached to the thoracic spine (T3) with tape and to the humerus with a specially designed cuff. During active scapular plane elevation, the scapula upwardly rotated (mean [SD] = 50 degrees [4.8 degrees ]), tilted posteriorly around a medial-lateral axis (30 degrees [13.0 degrees ]), and externally rotated around a vertical axis (24 degrees [12.8 degrees ]). Lowering of the arm resulted in a reversal of these motions in a slightly different pattern. The mean ratio of glenohumeral to scapulothoracic motion was 1.7:1. Normal scapular motion consists of substantial rotations around 3 axes, not simply upward rotation. Understanding normal scapular motion may assist in the identification of abnormal motion associated with various shoulder disorders.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomechanical Phenomena
  • Bone Nails
  • Female
  • Humans
  • Male
  • Range of Motion, Articular / physiology*
  • Scapula / physiology*
  • Shoulder Joint / physiology*
  • Spine