Flat bones in the human body include the ribs, sternum (breastbone), scapula (shoulder blade), pelvic girdle and many of the 29 bones that make up the skull. Flat bones act as protection for essential organs or as attachment points for major muscle groups.
The skull protects the brain, while the ribs and sternum protect vital internal organs like the heart, liver and lungs. The scapula and pelvic girdle act as larger attachment points for muscles.
The muscles attached to the two scapula bones control the rotation of the arms and shoulders. The scapula, together with the acromion bone, form the upper part of the shoulder socket.
The pelvic girdle consists of the three bones: the ilium, ischium and pubis. These bones support the muscles and movement of the trunk and those that allow leg and hip movements.