The deltoid muscle is located at the back of the shoulder.

• A. Upper arm muscle
• B. Chest
• C. Abs
• D. Back of the shoulder

Answer: (D)

Where the deltoid sits on the body. The deltoid is the large rounded muscle that cover the shoulder joint, attaching across the shoulder blade and collarbone to the upper arm. It wraps around the shoulder with three parts: front, middle, and back, so it sits over the shoulder from the front to the back. Describing it as at the back of the shoulder best captures its location on the shoulder region, especially its posterior portion, rather than being in the chest, abdomen, or upper arm. The other areas refer to different muscle groups entirely.