Which structure is typically involved in a joint?

The structure typically involved in a joint is cartilage, which serves multiple essential functions in the musculoskeletal system. Cartilage is a flexible connective tissue that covers the ends of bones where they meet to form joints. Its primary role is to provide a smooth, lubricated surface for articulation, facilitating the movement of bones against each other with reduced friction. Additionally, cartilage acts as a shock absorber, helping to distribute loads and provide cushioning during weight-bearing activities.

In contrast, tendons connect muscles to bones but do not directly participate in joint structure. Muscles provide movement by contracting but are not part of the joint itself. Skin is the outer covering of the body and does not have a role in the structure or function of joints. Thus, cartilage is integral to the formation and functioning of joints, making it the correct answer.