The huge part of the thoracic cage is created by the bones of the thorax and also it protects and supports to viscera (example, heart and lungs) which is located inside the thoracic cavity. The thoracic cage is featured to be active, but also dynamic at the same time as it keeps on moving at its different joints.
The bones of the thorax are:
The Sternum or Breast Bone is a long flat bone, which is enlarged about 7 cm long. It is located in the anterior median part of the chest wall.
The shape of the sternum somewhat resembles to a small sword or a dagger. Sternum comprises of 3 parts, namely – manubrium, body, and xiphoid process that respectively acts to the handle, blade, and point of the sword.
It is almost quadrilateral in shape. It is located opposite to the 3rd and fourth thoracic vertebrae. It’s the thickest and most powerful part of the sternum
The ribs stretches posteriorly from thoracic vertebrae to the anterior lateral edges of the sternum. They are ribbon like, elastic bony arches and flat in shape. Coastal cartilages are joined to the anterior ends. The costal cartilage and ribs together makes the costa. Also the large part of the thoracic skeleton is created by the ribs and their costal cartilages.
Lumbar Vertebrae are the five individual cylindrical bones that form the shape of the spine in the lower back.The components contained by the lumbar vertebrae are same as the thoracic vertebrae but to carry the greater load, these components are gigantic. There are 5 lumbar vertebrae out of which first 4 (L1 to L4) are typical and fifth (L5) is atypical.