This document discusses joints and their classification. It begins by defining arthrology as the study of joints, which connect two or more bones and allow movement. Joints are classified based on structure and function. Structurally, they are fibrous, cartilaginous, or synovial. Functionally, they are synarthroses (immovable), amphiarthroses (slightly movable), or diarthroses (freely movable). Synovial joints have the most movement and include ball-and-socket, hinge, and pivot joints. The document then describes characteristics of different joint types and provides examples.