OSMT (Ontario Society of Medical Technologists) Practice Exam

An antagonist to a muscle that flexes the arm would be a muscle that:

1. a. adducts the arm

2. b. abducts the arm

3. c. extends the arm

4. d. rotates the arm

The correct answer is: c. extends the arm

The correct answer is the muscle that extends the arm. An antagonist in muscle action refers to a muscle that opposes the motion of another muscle. When a muscle flexes the arm, such as the biceps brachii, the antagonist would be responsible for the opposite action, which is extending the arm. The triceps brachii is a prime example of a muscle that extends the arm, effectively opposing the flexing action. In this context, adduction, abduction, and rotation of the arm involve different motions that do not directly counteract the flexion action. Adduction brings the arm closer to the body, abduction moves it away from the body, and rotation involves turning around the shoulder joint. These actions are not opposite to arm flexion and therefore do not fit the definition of an antagonist in this scenario.