diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
index b623a03fb70..00e9c3ac04b 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
@@ -157,7 +157,10 @@ namespace internal{
  * @param np optional sequence of \ref pmp_namedparameters "Named Parameters" among the ones listed below
  *
  * \cgalNamedParamsBegin
- *    \cgalParamBegin{vertex_point_map} the property map with the points associated to the vertices of `pmesh` \cgalParamEnd
+ *    \cgalParamBegin{vertex_point_map} the property map with the points associated to the vertices of `pmesh`
+ *      If this parameter is omitted, an internal property map for
+ *      `CGAL::vertex_point_t` must be available in `TriangleMesh`
+ *    \cgalParamEnd
  *    \cgalParamBegin{geom_traits} a geometric traits class instance \cgalParamEnd
  * \cgalNamedParamsEnd
  *
@@ -181,7 +184,6 @@ bool is_outward_oriented(const PolygonMesh& pmesh,
   if (faces(pmesh).first == faces(pmesh).second)
     return true;
 
-
   using parameters::get_parameter;
 
   //VertexPointMap
@@ -676,6 +678,8 @@ void set_cc_intersecting_pairs(
  * \cgalNamedParamsBegin
  *   \cgalParamBegin{vertex_point_map}
  *     the property map with the points associated to the vertices of `tm`.
+ *     If this parameter is omitted, an internal property map for
+ *     `CGAL::vertex_point_t` must be available in `TriangleMesh`
  *   \cgalParamEnd
  *   \cgalParamBegin{face_index_map}
  *     a property map containing a unique id per face of `tm`, in the range `[0, num_faces(tm)[`.