function measureBetaAngle(obj)
  % Glenoid BETA angle is the angle between the floor of the supraspinatus fossa 
  % marked by a sclerotic line and the glenoid fossa line. The floor of the 
  % supraspinatus fossa is the line fitted to the scapular groove points.
  % The glenoid fossa line is the glenoid supero-inferior line.
  supraspinatusFossaFloor = Vector(fitLine(obj.scapula.groove)')
  supraspinatusFossaFloor = supraspinatusFossaFloor.orientToward(obj.scapula.coordSys.ML); 
  betaRotation = vrrotvec(supraspinatusFossaFloor.vector, -obj.inferoSuperiorLine.vector);

  % Unlike glenoid retroversion angle, glenoid beta angle method doesn't set
  % the sign of this angle which should be compared to the rotation axis alignment
  % with scapular PA axis. However, this alignement depends on the shoulder side.
  % It's assumed that glenoid supero-inferior line will always be aligned with
  % scapular SI axis, and supraspinatusFossaFloor line will always be aligned 
  % with scapular ML axis. Therefore glenoid beta angle will always be a 
  % positive number.
  obj.beta = rad2deg(betaRotation(4));
end