Courteney Cox -- Breaks Wrist In Mexico

Es no bueno ... Courteney Cox's Cancun vacation was cut short, when she fell and broke her wrist Saturday -- leaving her no choice but to hightail it back to the states. Ay Caramba.

Our sources tell us ... Courteney was chillin' with friends south of the border when it happened. We're told she somehow slipped and when she tried to break her fall, her wrist snapped. Doctors came to her hotel room and confirmed it was pretty bad.

So much so, the medicos put a cast on the busted limb -- but Courteney wasn't taking any chances and booked a private jet to take her stateside ASAP ... to get treated by her own physicians. It's unclear if surgery will be necessary.

Lo siento.