The shoulder blade.
Origin of blade
- Middle English from Old English blæd bhel-3 in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- From Middle English, from Old English blæd (“leaf”), from Proto-Germanic *bladą (compare West Frisian bled, Dutch blad, German Blatt, Danish blad) from Proto-Indo-European *bʰlh̥₃oto (compare Irish bláth (“flower”), Tocharian A pält, Tocharian B pilta (“leaf”), Albanian fletë (“leaf”)), from *bʰleh₃- (“to thrive, bloom”). Similar usage in Sägeblatt (“saw leaf”), the German term for a saw blade. More at blow.