Rails 3.1 Active Record - loading the parent object in a has_many :through relationship

I have the following class structure for an app I'm porting from php to rails:

class Menu < ActiveRecord::Base
  has_many :menu_headers
  has_many :menu_items, :through => :menu_headers
end

class MenuHeader < ActiveRecord::Base
  acts_as_tree :parent_id
  has_many :menu_items
  belongs_to :menu
end

class MenuItem < ActiveRecord::Base
  belongs_to :menu_heade开发者_如何学运维rs
end

How would I load the MenuHeader or Menu for a specific MenuItem?

Like:

ruby-1.9.2-p290 :004 > @b=Menu.find(1)  #works
ruby-1.9.2-p290 :005 > @b.menu_headers  #works
ruby-1.9.2-p290 :006 > @b.menu_items    #works

ruby-1.9.2-p290 :004 > @mi=MenuItem.find(1) #works
ruby-1.9.2-p290 :005 > @mi.menu_headers     #doesn't work
ruby-1.9.2-p290 :006 > @mi.menus            #doesn't work

thx

---

You need singular associations as follows:

class MenuItem < ActiveRecord::Base
  belongs_to :menu_header
  has_one :menu, :through => :menu_header
end