Explain how the elbow joint works to move bones closer or further apart.

Answer:

The elbow joint functions as a hinge joint moved by antagonistic pairs of muscles. To move the bones closer together, the biceps muscle contracts while the triceps relaxes. To move the bones further apart, the triceps muscle contracts and the biceps relaxes. The joint contains synovial fluid to reduce friction between the bones, and cartilage allows the joint to resist wear and tear.