Yes, ETHMOIDS is a Scrabble word!

Letter values in Scrabble US: E 1, T 1, H 4, M 3, O 1, I 1, D 2, S 1.

Is it a valid word?

ETHMOIDS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

one of the eight bones of the cranium; a small bone filled with air spaces that forms part of the eye sockets and the nasal cavity

Also: ethmoid bone.