node/add/page

index.php

   menu_execute_active_handler();

     call_user_func_array($router_item['page_callback'],
                          $router_item['page_arguments']);

     node_add(); 

       $output = drupal_get_form($type .'_node_form', $node);

         drupal_render_form($form_id, $form);

           $output = drupal_render($form);

             theme($elements['#theme'], $elements);

             $content .= drupal_render($elements[$key]);

   print theme('page', $return);  // theme used here is in directory themes