Which term refers to the movement that brings long bones on either side of a joint closer together?

Flexion is the movement that decreases the angle between the long bones on either side of a joint, effectively bringing them closer together. This occurs primarily at hinge joints like the elbow and knee, where the movement results in bending. During flexion, the bones that form the joint come closer, which is essential for many daily activities like bending over or lifting objects. For example, when you flex your arm at the elbow, your forearm moves closer to your upper arm.

In contrast, rotation refers to turning a bone around its own axis, while extension increases the angle between bones, moving them further apart. Abduction involves moving a limb away from the midline of the body, which also does not relate to bringing bones closer together. Therefore, flexion is specifically the term that describes the movement of bringing long bones closer at a joint.