Kaplan Nursing Entrance Practice Exam

Which type of muscle is responsible for bending a joint?

1. Cardiac muscle

2. Skeletal muscle

3. Flexor muscle

4. Extensor muscle

The correct answer is: Flexor muscle

The muscle responsible for bending a joint is known as a flexor muscle. Flexor muscles contract to decrease the angle between two bones at a joint, effectively creating a bending motion. This is crucial for many movements, such as bending the elbow or knee. While skeletal muscle is indeed responsible for voluntary movements, it encompasses both flexors and extensors, making it a broader category. Cardiac muscle is specifically found in the heart and is not involved in joint movement. Extensor muscles serve the opposite function; they increase the angle at a joint, leading to straightening rather than bending. Therefore, flexor muscles are specifically designated for this bending action, making them the correct choice in this context.