Nav not updating on $scope change - angularjs

Question

I have a content controller and a header controller in my Angular app. The content controller has the ability to add items to array of objects. The header controller puts these items into the navigation.
On load the header controller successfully loads the existing items from the database and adds them to the global scope, they then show up in the nav thanks to an ng-repeat.
When the content controller adds a new item to the global scope though it's not reflected in the header. I can log out the contents of the global scope and the new item is there, it just doesn't want to show up in the dom. Using $apply() doesn't seem to make any difference.
Here's the 2 controllers:
HeaderCtrl:
angular.module('system').controller('HeaderController', ['$scope', 'Global', 'Lists', function ($scope, Global, Lists) {
$scope.global = Global;
$scope.find = function() {
Lists.query(function(lists) {
$scope.global.lists = lists;
});
};
}]);
ContentCtrl:
angular.module('lists').controller('ListsController', ['$scope', '$routeParams', '$location', '$http', 'Global', 'Lists', function ($scope, $routeParams, $location, $http, Global, Lists) {
$scope.global = Global;
$scope.create = function() {
var list = new Lists({
name: this.name,
});
list.$save(function(response) {
$location.path('lists/' + response._id);
$scope.global.lists.push(response);
});
};
}]);
Like I say a console log from the Header Controller shows that the new item is present in $scope.global.lists but it doesn't get reflected in the DOM. Any ideas?

Answer 1

Use a $rootScope event and catch it in the header whenever you update the other controller:
//main ctrl
$rootScope.$broadcast("updateHeader", someInfoToSend);
//header ctrl
$scope.$on("updateHeader", function(e, someInfoReceived){
// do the necessary updates here
});

Answer 2

It was a small data mismatch between existing items and the newly added item that was causing the issue.
The items from the database had a property of
owner: {
"_id" : "213876512461"
}
Whereas the data returned from the adding of a new item had
owner: "213876512461"
Because of this an ng-hide directive was incorrectly hiding the newly added item.
I've marked ruedamanuel's answer up, as I've ended up using his $broadcast method to let the main controller update $scope.lists in the header controller, negating the need to use $rootScope or a global variable.