Skree and Skrelbow

My skrelbow is frontside of my elbow.
It bends and helps me do many things.
There's a mole on my right skrelbow.
Not the kind that lives in a hole.

My skree is the backside of my knee.
It's like my underarm but bends my knee you see?
When I stand or when I sit, my skree always bends for me.

My skrelbow is the inside of my elbow.
My skree is the other side of my knee.