The radius, ulna, and humerus are involved in what type of joint?

The radius, ulna, and humerus are involved in hinge joints primarily because this type of joint allows for movement in one plane, enabling actions such as flexion and extension. In the arm, the elbow joint is a classic example of a hinge joint where the humerus, connecting with the ulna and radius, facilitates bending (flexion) and straightening (extension) of the arm.

The structure of a hinge joint is characterized by a convex surface of one bone fitting into a concave surface of another, which permits this uniaxial movement. The elbow is specifically designed for this function, allowing the forearm to move towards and away from the upper arm without significant lateral movement, which is a defining characteristic of hinge joints.

In contrast, the other joint types listed have different movement capabilities; ball and socket joints allow for a greater range of motion in multiple directions, pivot joints enable rotational movement around a single axis, and plane joints facilitate gliding movements, none of which describe the primary movement mechanics of the elbow joint involving the radius, ulna, and humerus.