What is a synovial joint?

• A. Bones connected by a synovial capsule with a joint cavity.
• B. Made of fibrocartilage with little movement.
• C. Bones separated by a fluid-filled joint cavity that allows for lubrication such as ball and socket joints, hinge and condylar.
• D. Bones fused by bone tissue with no movement.

Answer: (C)

The key idea is recognizing what defines a synovial joint: it features a fluid-filled joint cavity that provides lubrication, allowing smooth movement between the bones. In a synovial joint, the bones are separated by this cavity and wrapped in a joint capsule, with synovial fluid inside to reduce friction and nourish the cartilage. This setup enables the diverse movements seen in joints like ball-and-socket, hinge, and condylar.

That’s why the best choice is the one that describes bones separated by a fluid-filled joint cavity that allows lubrication, and notes the types of joints where this applies. The other descriptions point to different joint types—some lack the explicit fluid-filled cavity, some describe joints with limited movement due to fibrocartilage, and others describe joints with no movement due to bone fusion.