The joint type that allows the greatest range of motion is which?

• A. Fibrous joints
• B. Cartilaginous joints
• C. Bony joints
• D. Synovial joints

Answer: (D)

Synovial joints allow the greatest range of motion because their structure creates a fluid-filled cavity between the articulating bones, combined with smooth articular cartilage, a tough joint capsule, and supporting ligaments. The synovial fluid lubricates and reduces friction, so the joints can move freely. The shape of the articulating surfaces and the capsule provide stability, while the ligaments permit extensive movement without letting the bones dislocate. This setup supports many directions of movement—from bending and straightening to sliding and rotating—especially in multi-axial joints like the shoulder or hip.

In contrast, fibrous joints lack a joint cavity and are tightly bound by dense connective tissue, offering little to no movement. Cartilaginous joints bridge bones with cartilage and allow some movement, but not as much as synovial joints. Bony joints are fused, resulting in no movement at all.