skeletal structure

NOUN
18 LETTERS · STARTS WITH S

skeletal structure is a valid 18-letter word worth 23 points in Scrabble and 28 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1K5E1L1E1T1A1L1S1T1R1U1C3T1U1R1E1
1 + 5 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 1 + 1 =23 PTS
DOUBLE WORD → 46TRIPLE WORD → 69
MEANING

What does skeletal structure mean?