Looping through multi-dimmensional array

[Good2CU]

I want to loop through a multi-dimmensional array, and output the key's of both inner and outer as text.

$multi_array = array('x' => array(1), 'y' => array(2), 'z' => array(3));	

foreach ($multi_array as $outer) {
     echo "{$outer}<br />";
}

There would also be an inner loop, but that is working fine, so I won't include it here. I want the above to output x y z, but instead it outputs array, array, array

How do I get it to do x y z?

Thanks

[Horizon88]

Try array_keys()

[Good2CU]

If I make this modification:

foreach (array_keys($multi_array) as $outer) {

I get this error for each outer element when the script gets to the inner for eacheach loop:
Invalid argument supplied for foreach()

the innter statement looks like this:
foreach ($outer as $inner => $value) {

Thanks

[NogDog]

foreach($array_name as $key => $value)
{
   echo "Key: $key, Value: $value<br />\n";
}