Which bone forms the shoulder blade?

• A. Humerus
• B. Scapula
• C. Clavicle
• D. Sternum

Answer: (B)

The shoulder blade is the scapula, a flat, triangular bone that sits on the back of the rib cage and is part of the shoulder girdle. It forms the socket for the arm at the glenoid cavity, where it articulates with the head of the humerus to create the shoulder joint. It also features structures like the acromion and spine that serve as muscle attachment sites and help shape the shoulder’s outer contour. The other bones listed don’t form the shoulder blade: the humerus is the upper arm bone, the clavicle is the collarbone that connects the sternum to the scapula, and the sternum is the central chest bone. So the scapula is the bone that forms the shoulder blade.