How do you find out how many skulls you have captured ? Halo 3?

[candy sweet]

My brother is playing halo 3 & he doesn't know how to go to the screen that shows how many skulls you have captured?
Please help !!We are wayyy confused Send me a instant message on anyother yahoo my other yahoo is [email protected]

 

[Snake]

when you go to the campaign screen push x to see scoring and skulls