As this is Oreos thread, i'll keep it short....
I have 2/3rds of the active muscle in my shoulders, and my bicepts, and can move my wrist in 1 direction, so palm down wrist moves up... Helps with typing. While i have movement, my strength in them isn't super, bout 3/4s the norm, and gets less as you go down my arm... so wrist strength is like 10%....
So i can move my arms, until they go over my head at which time i smack myself in the head... lack of tricepts.