Which movement occurs when you bend the arm at the elbow?

Bending the arm at the elbow involves reducing the angle between the forearm and the upper arm, which is the essence of flexion. This movement typically occurs at hinge joints, like the elbow, where one bone (the humerus) moves relative to another (the radius and ulna) to close the angle. During flexion, the biceps brachii and brachialis muscles contract to bring the forearm closer to the shoulder, which is essential for many daily tasks.

In contrast, extension would involve straightening the arm at the elbow, increasing the angle between the upper arm and forearm. Dorsiflexion refers to the movement at the ankle where the toes are brought closer to the shin, while retraction is a movement that pulls a body part backward, such as moving the shoulder blades together. Therefore, flexion specifically describes the action of bending the arm at the elbow, making it the correct answer.