scapula (n.)youdaoicibaDictYouDict[scapula 词源字典]
"shoulder blade," 1570s, Modern Latin, from Late Latin scapula "shoulder," from Latin scapulae (plural) "shoulders, shoulder blades," perhaps originally "spades, shovels," on notion of similar shape, but animal shoulder blades might have been used as scraping tools in primitive times, from PIE *skap-, variant of *skep- "to cut, scrape" (see scabies).[scapula etymology, scapula origin, 英语词源]
spade (n.2)youdaoicibaDictYouDict
black figure on playing cards," 1590s, probably from Italian spade, plural of spada "the ace of spades," literally "sword, spade," from Latin spatha "broad, flat weapon or tool," from Greek spathe "broad blade" (see spade (n.1)). Phrase in spades "in abundance" first recorded 1929 (Damon Runyon), probably from bridge, where spades are the highest-ranking suit.
The invitations to the musicale came sliding in by pairs and threes and spade flushes. [O.Henry, "Cabbages & Kings," 1904]
Derogatory meaning "black person" is 1928, from the color of the playing card symbol.