The structure of the rib cage. In your body, the framework of the chest is called the thoracic cage or in common terminology, the rib cage. Its design functions to protect vital organs such as your heart and lungs and also provides points of attachment for many muscles. The thoracic or rib cage is comprised of three main parts, the sternum, the ribs, and the thoracic vertebrae.
The sternum, also called the breastbone, is located in the middle of your chest and it is composed of three parts. The manubrium is the widest part at the top of the bone, the body located in the middle, and the xiphoid process at the bottom. There are a total of 12 ribs and they originate on or between the thoracic vertebrae in the vertebral column and they wrap around the sides of your body and end in the front of your body. Ribs one through seven are called true ribs because they individually connect to the sternum.
by way of cartilaginous extensions called coastal cartilages, which you can see here in this model. Ribs 8 through 12, located at the bottom of the rib cage, are called false ribs because they do not directly connect to the sternum from their own coastal cartilages. Ribs 8 through 10 fuse with the coastal cartilage of rib 7 and ribs 11 and 12 are called floating ribs because they do not connect with the sternum at all.
The thoracic vertebrae make up the thoracic curvature in the vertebral column. as you can see here. Each of the 12 ribs articulate or form a joint with the corresponding vertebra.
So for example, rib 11 articulates with vertebra T11 and some of the ribs such as rib 9 articulates with T9 and the vertebra above T8. And that be the basics on the structure of the rib cage.