diff --git a/ShoulderCase/@Humerus/Humerus.m b/ShoulderCase/@Humerus/Humerus.m
index b08a523..a575f10 100644
--- a/ShoulderCase/@Humerus/Humerus.m
+++ b/ShoulderCase/@Humerus/Humerus.m
@@ -1,100 +1,105 @@
 classdef Humerus < handle
   %HUMERUS Properties and methods associated to the humerus
   %   Detailed explanation goes here
 
   % Author: Alexandre Terrier, EPFL-LBO
   % Creation date: 2018-07-01
   % Revision date: 2019-06-29
   %
   % TO DO:
   %   Local coordinate system
 
 
   properties
     landmarks % 5 3D points
     insertions
+    insertionsRing
     center % Center of the humeral head (sphere fit on 5 points
     radius % Radius of the humeral head (sphere fit on 5 points
     jointRadius % Radius of cuvature of the articular surface (todo)
     SHSAngle % Scapulo-humeral subluxation angle
     SHSPA % Scapulo-humeral subluxation angle in the postero-anterior direction (posterior is negative, as for glenoid version)
     SHSIS % Scapulo-humeral subluxation angle in the infero-superior direction
     SHSAmpl % Scapulo-humeral subluxation (center ofset / radius)
     SHSOrient % Scapulo-humral subluxation orientation (0 degree is posterior)
     GHSAmpl  % Gleno-humeral subluxation (center ofset / radius)
     GHSOrient % Gleno-humral subluxation orientation (0 degree is posterior)
     subluxationIndex3D
     shoulder
   end
 
   methods (Access = ?Shoulder) % Only Shoulder is allowed to construct Humerus
     function obj = Humerus(shoulder)
       %HUMERUS Construct an instance of this class
       %   Detailed explanation goes here
       obj.landmarks = [];
-      obj.center    = [];
-      obj.radius    = [];
+      obj.insertionsRing = [];
+      obj.center = [];
+      obj.radius = [];
       obj.jointRadius = [];
-      obj.SHSAngle  = [];
-      obj.SHSPA     = [];
-      obj.SHSIS     = [];
-      obj.SHSAmpl   = [];
+      obj.SHSAngle = [];
+      obj.SHSPA = [];
+      obj.SHSIS = [];
+      obj.SHSAmpl = [];
       obj.SHSOrient = [];
-      obj.GHSAmpl   = [];
+      obj.GHSAmpl = [];
       obj.GHSOrient = [];
       obj.shoulder = shoulder;
     end
   end
 
   methods
     function output = loadData(obj)
       % Call methods that can be run after the ShoulderCase object has
       % been instanciated.
       if obj.hasSlicerLandmarks()
         success = Logger.timeLogExecution(...
           "Humerus load landmarks (slicer): ",...
           @(obj) obj.loadSlicerLandmarks, obj);
       elseif obj.hasAmiraLandmarks()
         success = Logger.timeLogExecution(...
           "Humerus load landmarks (amira): ",...
           @(obj) obj.loadAmiraLandmarks, obj);
       else
         success = Logger.timeLogExecution(...
           "Humerus load landmarks: ",...
           @(message) error(message), "No landmarks file found");
       end
       output = success;
     end
 
     function output = morphology(obj)
       % Call methods that can be run after loadData() methods has been run 
       % by all ShoulderCase objects.
       success = Logger.timeLogExecution(...
         "Humerus center and radius: ",...
         @(obj) obj.measureCenterAndRadius, obj);
+      success = success & Logger.timeLogExecution(...
+        "Insertions' ring: ",...
+        @(obj) obj.measureInsertionsRing, obj);
       output = success;
     end
 
     function output = measureFirst(obj)
       % Call methods that can be run after morphology() methods has been run 
       % by all ShoulderCase objects.
       success = Logger.timeLogExecution(...
         "Humerus scapulo-humeral subluxation: ",...
         @(obj) obj.measureScapuloHumeralSubluxation, obj);
       output = success;
     end
     
     function output = measureSecond(obj)
       % Call methods that can be run after measureFirst() methods has been run 
       % by all ShoulderCase objects.
       success = Logger.timeLogExecution(...
         "Humerus gleno-humeral subluxation: ",...
         @(obj) obj.measureGlenoHumeralSubluxation, obj);
       success = success & Logger.timeLogExecution(...
         "Humerus 3D subluxation index: ",...
         @(obj) obj.measureSubluxationIndex3D, obj);
       output = success;
     end
   end
 
 end
diff --git a/ShoulderCase/@Humerus/measureInsertionsRing.m b/ShoulderCase/@Humerus/measureInsertionsRing.m
new file mode 100644
index 0000000..9b4e9d6
--- /dev/null
+++ b/ShoulderCase/@Humerus/measureInsertionsRing.m
@@ -0,0 +1,27 @@
+function measureInsertionsRing(obj)
+  % The insertions ring is the intersection of the plane fitted to the
+  % insertions' landmarks with the humeral head fitted sphere.
+
+  insertionsArray = [];
+  for insertionName = string(fields(obj.insertions))'
+    insertionsArray = [insertionsArray; obj.insertions.(insertionName)];
+  end
+  insertionsPlane = Plane();
+  insertionsPlane.fit(insertionsArray);
+
+  ringNormal = Vector(insertionsPlane.normal);
+  humerusCenterToPlanePoint = Vector(obj.center, insertionsPlane.point);
+
+  % The ring's center is the projection of any point of the insertions' plane
+  % on the vector starting at the humeral head center and with the same 
+  % direction as the insertion's plane normal direction.
+  ringCenter = obj.center...
+    + (ringNormal.dot(humerusCenterToPlanePoint) * ringNormal.vector);
+
+  humerusCenterToRingCenter = Vector(obj.center, ringCenter);
+  ringRadius = sqrt(obj.radius^2 - humerusCenterToRingCenter.norm()^2);
+    
+  obj.insertionsRing.center = ringCenter;
+  obj.insertionsRing.radius = ringRadius;
+  obj.insertionsRing.normal = ringNormal;
+end
\ No newline at end of file