1.3. The Sternum
There are three main parts of the sternum. These are the:
The ribs themselves do not directly articulate with the sternum. In-between each rib and the sternum lies costal cartilage. The chondrosternal junction/joint, where the cartilage articulates with the sternum, allows considerable expansion of the thoracic cavity. The costal cartilages are made of hyaline cartilage (this type of cartilage is very common throughout the body). The costochondral junction/joint is of less importance in expansion of the thoracic cavity.
Anatomical Landmarks of Note
The jugular notch (which is also called the suprasternal notch) is a major anatomical landmark that is really easy to palpate on yourself - run your fingers along your clavicles medially, towards your sternum, and notice a U-shaped depression of about 1cm in between the ends of the clavicles. This is the jugular notch of the manubrium. Approximately 2cm below this you should feel a raised horizontal ridge. This is the sternal symphysis. The sternal symphysis is the joint between the manubrium and sternal body. It is classified as a 'symphysis'. A symphysis joint is also called a secondary cartilaginous joint (read more about these in Section 1.5.).