diff --git modules/system/system.api.php modules/system/system.api.php
index c68d893..6c9a0d6 100644
--- modules/system/system.api.php
+++ modules/system/system.api.php
@@ -1002,12 +1002,14 @@ function hook_page_build(&$page) {
  *     item. Note that this function is called even if the access checks fail,
  *     so any custom delivery callback function should take that into account.
  *     See drupal_deliver_html_page() for an example.
- *   - "access callback": A function returning a boolean value that determines
- *     whether the user has access rights to this menu item. Defaults to
- *     user_access() unless a value is inherited from a parent menu item.
+ *   - "access callback": A boolean value or a number that can be cast to a
+ *     boolean value, that determines whether the user has access rights to this
+ *     menu item. Note that this value can be either set by the return value of
+ *     a function or set explicitly. Defaults to user_access() unless a value is
+ *     inherited from a parent menu item.
  *   - "access arguments": An array of arguments to pass to the access callback
  *     function, with path component substitution as described above.
- *   - "theme callback": Optional. A function returning the machine-readable
+ *   - "theme callback": (optional) A function returning the machine-readable
  *     name of the default theme that will be used to render the page. If this
  *     function is provided, it is expected to return a currently-active theme
  *     on the site (otherwise, the main site theme will be used instead). If no