function measurePlane(obj)
  % Scapular plane is fitted on 3 points (angulusInferior,
  % trigonumSpinae, most laretal scapular goove landmark).
  inferior = obj.angulusInferior;
  medial = obj.trigonumSpinae;
  mostLateralGrooveIndex = findLongest3DVector(medial-obj.groove);
  mostLateralGroovePoint = obj.groove(mostLateralGrooveIndex(1),:);

  obj.plane.fit([inferior; medial; mostLateralGroovePoint]);

  anterior = obj.processusCoracoideus;
  posterior = obj.angulusAcromialis;
  obj.plane.normal = orientVectorToward(obj.plane.normal,(anterior-posterior));
end