How does Drupal 7 determine the output of user menu? I have the built in User Menu being displayed in a region of my template with the following code:

render($page['user_menu']);


Drupal seems to automatically handle where thsis should be output. Generally it outputs in the /user/* pages.

However, I have recently started working on a custom module that had added a new menu item to /user/my_module but when I visit the page the User Menu is not displayed.

Could someone tell me how Drupal manages the output of the User Menu or possibly how to get it to display on this page/path?
You need to set menu_name for your menu item to user-menu, see userpoints_menu() for an example (the myuserpoints menu item).