diff --git a/doc/user-manual/fpakc_UserManual.tex b/doc/user-manual/fpakc_UserManual.tex
index 4820a36..d662c6c 100644
--- a/doc/user-manual/fpakc_UserManual.tex
+++ b/doc/user-manual/fpakc_UserManual.tex
@@ -613,6 +613,9 @@ make
           
         \end{itemize}
       
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+      \subsection{physicalSurfaces}
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
       \subsection{inject}
         The array \textbf{inject} specifies the injection of particles from different surfaces.