The prime mover of elbow flexion is ____________. brachialis triceps brachii biceps brachii coracobrachialis brachioradialis

The prime mover of elbow flexion is primarily the biceps brachii.

Explanation:

1. Function of Biceps Brachii: The biceps brachii muscle is a two-headed muscle located on the upper arm. Its main functions are to facilitate elbow flexion and forearm supination. During the action of bending the elbow, the biceps brachii contracts, pulling the forearm up towards the shoulder.

2. Other Muscles Involved:

   • The brachialis also plays a crucial role in elbow flexion, serving as the primary muscle when the forearm is in a pronated position. However, it is not the prime mover due to the more significant action of the biceps brachii.
   • The triceps brachii acts as an antagonist during elbow flexion, working to extend the elbow opposite to this motion.
   • Coracobrachialis and brachioradialis assist in flexion but are not the primary movers for elbow flexion.

In conclusion, while several muscles contribute to the action of elbow flexion, the biceps brachii is the most significant and is often considered the prime mover in this movement.