" My better parts Are all thrown down, and that which here stands up Is but a quintain, a mere lifeless block." please explain this.

ORLANDO

(to himself) Can’t I even say “thank you”? I left my brain back on the wrestling field. What’s left of me is a dummy, just a lifeless block.

Source No fear Shakespeare

He' squestioning why he can't even say thank you, and stating that all of his good qualities, like his ability to speak are useless.......... he feels like a useless, inANIMATE STONE... stupid, so to speak.