This is a sketch, done from memory, of an old woman that I've seen a few times. I was less concerned about creating a perfect likeness of her and more focused on producing a caricature that captured her general essence.
What I found interesting about her was (and I admit this sound odd) was her upper arms. I've seen flabby arms before but never quite like this. The fat had accumulated considerably around her bicep while her forearm was relatively lean and "average" for a woman her age. It made her arms resemble two rather worn pencils, each shoved into a mound of putty.
I didn't think the drawing above adequately depicts her arms so I provided an isolated view of one below that is slightly more successful.