sphincter muscle

NOUN
16 LETTERS · STARTS WITH S

sphincter muscle is a valid 16-letter word worth 26 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1P3H4I1N1C3T1E1R1M3U1S1C3L1E1
1 + 3 + 4 + 1 + 1 + 3 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 3 + 1 + 1 =26 PTS
DOUBLE WORD → 52TRIPLE WORD → 78
MEANING

What does sphincter muscle mean?