Navigation menu in PHP

this is the basic concept of how i handle navigation in PHP.
it's not commented but it's very basic but if there is something you want to ask, just ask on this blog :)

<?php
 $prefix = '/path/to/file/myPrefix.';
 $postfix = '.inc.php';
 $defaultPage = 'home';
 $errorPage = '404';

 $incFile = $prefix . $_GET['page'] . $postfix;
 $default = $prefix . $defaultPage . $postfix;
 $error = $prefix . $errorPage . $postfix;
 if(file_exists($incFile))
 {
  switch($_GET['page'])
  {
   case 'home':
   case 'about':
   case 'contact':
     include_once $incFile;
    break;

   case '':
     @include_once $default;
    break;

   default:
     @include_once $error;
    break;
  }
 }
 else
 {
  echo '<h1>Page Not Found: 404</h1>';
 }
?>