Final answer:
The structural classifications of joints are fibrous, cartilaginous, and synovial joints.
Step-by-step explanation:
The three structural classifications of joints are fibrous joints, cartilaginous joints, and synovial joints.
Fibrous Joints: These joints are connected by dense connective tissue, predominantly collagen fibers. They provide minimal movement and include sutures between skull bones and syndesmosis joints like the tibia and fibula.
Cartilaginous Joints: These joints are connected by cartilage. There are two types: synchondroses, where hyaline cartilage connects bones (e.g., costal cartilage attaching ribs to the sternum), and symphyses, where fibrocartilage connects bones (e.g., intervertebral discs).
Synovial Joints: These joints have a synovial cavity filled with synovial fluid, allowing free movement. Examples include the knee, elbow, and shoulder joints. Synovial joints are further classified into various types based on their structure and range of motion.