Yes, SCALENI is a Scrabble word!

Letter values in Scrabble US: S 1, C 3, A 1, L 1, E 1, N 1, I 1.

Is it a valid word?

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

any of four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing

Also: scalene muscle, musculus scalenus.