| 1. | Anatomy. a large, triangular muscle covering the joint of the shoulder, the action of which raises the arm away from the side of the body. |
| 2. | Anatomy. pertaining to or involving the deltoid. |
| 3. | Also, deltoidal. in the shape of a Greek capital delta (Δ); triangular. |
deltoid del·toid (děl'toid')
adj.
Of or relating to the deltoid muscle.
Triangular in shape or outline.
deltoid
large, triangular muscle that covers the shoulder and serves mainly to raise the arm laterally. The deltoid, as it is commonly known, originates on the outer front third of the clavicle (collarbone) and the lower margin of the spine of the scapula (shoulder blade). Its fibres unite to form a thick tendon that inserts at the deltoid tuberosity, a rough spot above the middle of the outer surface of the humerus (upper arm bone).
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