Final answer:
The first through tenth costochondral unions are cartilaginous joints known as synchondroses, involving hyaline cartilage and classified as synarthroses due to their immobility.
Step-by-step explanation:
The joint type of the first through tenth costochondral unions between costal cartilage and ribs is a cartilaginous joint. Specifically, these joints are classified as synchondroses, which is a type of cartilaginous joint where the bones are united by hyaline cartilage. The costochondral unions are examples of permanent synchondroses found in the thoracic cage, where the anterior ends of the ribs are joined to their respective costal cartilages. These joints do not ossify with age and are functionally classified as synarthroses, which means they are immobile or nearly immobile joints. It's worth mentioning that the first sternocostal joint is also a synchondrosis, but the remaining costal cartilages to the sternum are synovial joints.