Which muscle primarily functions to flex the elbow?

The muscle that primarily functions to flex the elbow is the brachioradialis. This muscle is located in the forearm and plays a significant role in the flexion of the elbow, especially when the forearm is in a neutral position (such as when the palm is facing the body).

While the biceps brachii is also a major elbow flexor, the question specifically focuses on the muscle that is responsible for flexing the elbow in various positions, making the brachioradialis the most appropriate choice in this context. The brachioradialis is especially activated during activities that involve lifting, pulling, or carrying.

The other muscles listed, such as the biceps femoris, pectoralis major, and gastrocnemius, do not primarily contribute to elbow flexion. The biceps femoris is part of the hamstrings and is involved in knee flexion and hip extension. The pectoralis major is primarily involved in movements of the shoulder and not the elbow. The gastrocnemius is a calf muscle that plays a key role in plantar flexion of the ankle and also crosses the knee joint but does not flex the elbow. Thus, the brachioradialis is the correct answer for its