What are the ribs that attach to sterum by individual cartilagenous extensions?

The ribs that attach to the sternum by individual cartilaginous extensions are known as true ribs. In humans, there are seven pairs of true ribs. They are numbered from the top (first rib) to the bottom (seventh rib).

The true ribs are connected to the sternum by costal cartilages, which are flexible bands of connective tissue. These cartilages allow the ribs to move during breathing. The first seven pairs of ribs are also known as the sternal ribs because they attach directly to the sternum.

The costal cartilages of the true ribs are attached to the sternum in a slightly different way than the costal cartilages of the false ribs. The costal cartilages of the true ribs attach to the sternum at a joint called the sternoclavicular joint. This joint allows for a greater range of motion than the joints between the false ribs and the sternum.

The true ribs are responsible for protecting the heart, lungs, and other organs in the thoracic cavity. They also play an important role in breathing by helping to expand and contract the chest cavity.