Octagon Girl Brittney Palmer -- I Fractured My Beautiful Wrist ... But Won't Miss UFC 174

Brittney Palmer won't let a fractured wrist keep her from ring girl duties at UFC 174 in Vancouver later this month -- refusing doctors orders to wear a cast because ... well ... it's not hot.

Brittney says she was riding her skateboard through the Hollywood Hills last week and crashed hard -- fracturing her wrist in the process.

An orthopedic surgeon wanted to put the wrist in a hard cast -- and that's when Brittney put her foot down, telling the doc it simply wasn't gonna happen.

And why not? Simple ... Brit's gotta hold the cards at 174 and doesn't want a clunky cast on her arm to clash with her tiny bikini.

Or as she puts it, "No one wants to see an octagon girl sporting a dorky cast."