function measureSubluxationindex3D(obj)
% -	GL: (Glenoid Line) Line that joins the most anterior glenoid rim point and 
%         the most posterior glenoid rim point.
% -	HHv: (Humeral Head vector) Vector from the glenoid center to the humeral 
%         head’s fitted sphere center.
% -	HHp: (Humeral Head projection) Projection of HHv on GL.
% -	HHr: (Humeral Head radius) Humeral head’s fitted sphere radius.
%
% The 3D humeral subluxation index is the ratio of ||HHp|| + ||HHr|| over 2*||HHr||.
  GL = obj.shoulder.scapula.glenoid.posteroAnteriorLine;
  HHv = Vector(obj.shoulder.scapula.glenoid.center, obj.center);
  HHp = GL.project(HHv);
  HHr = obj.radius;
  obj.subluxationIndex3D = (HHp.norm + HHr) / (2*HHr);
end