WordPress: Add HTML to navigation menu

Question

<ul id="menu-primary">
    <li></li>
    <li></li>
    <li></li>
    <span></span> /* Add after the list items; before the closing </ul> tag */
</ul>

How to add <span> tags after the list items, to the WP-menu with id="menu-primary" ?

EDIT

<ul id="menu-primary">
    <li></li>
    <li></li>
    <li></li><li class="fix"></li> /* Add <li class="fix"></li> adjacent after the list items exactly as shown. */
</ul>

Answer 1

Why don't you create a class for the li ?

<ul id="menu-primary">
    <li class ="class"></li>
    <li class ="class"></li>
    <li class ="class"></li>
/* Add after the list items; before the closing </ul> tag */
</ul>