musculus deltoideus mus·cu·lus·deltoideus uncommon noun 1. a large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm Synonymsdeltoiddeltoid musclemusculus deltoideus Related words Broader terms skeletal muscle Parts rotator cuff WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
