PSI Barbering Practice Exam

The muscle of the forearm that rotates the radius outward and the palm upward is known as the ____________?

1. Pronator

2. Flexor

3. Supinator

4. Extensor

The correct answer is: Supinator

The supinator is the muscle responsible for rotating the radius outward and turning the palm upward, which is a motion known as supination. This action is crucial in various daily activities, such as holding or drinking from a cup, as it positions the hand in a way that the palm faces upward. The supinator muscle works in conjunction with other muscles in the forearm to achieve this motion. The other muscle groups mentioned have different functions. The pronator muscles are involved in turning the palm downward, while flexors and extensors primarily deal with the bending and straightening actions of the wrist and fingers. Understanding the specific actions of each muscle can greatly enhance one’s knowledge of anatomy and assist in practical applications in barbering and related fields.