Which of the following describes a flexor muscle?

A flexor muscle is defined as a muscle that bends a joint, allowing for a decrease in the angle between the bones that comprise the joint. This action is crucial for various movements in the body, particularly those involving the arms and legs. For instance, when you bend your elbow, the biceps brachii acts as a flexor, drawing the forearm closer to the upper arm. This fundamental function is essential for many daily activities, such as lifting, gripping, or sitting.

Understanding the role of flexor muscles provides insight into how they interact with other muscle groups. In contrast, the other options describe different muscle actions that are not characteristic of a flexor. A muscle that straightens a joint is known as an extensor, while a muscle that rotates a limb performs rotational movements. Additionally, muscles that stabilize a joint contribute to maintaining posture and support, separate from the bending action that is specific to flexors. Thus, identifying a flexor muscle appropriately as one that bends a joint is vital for recognizing its significance in movement and muscle function.