What is the distal attachment of the pronator teres?

The pronator teres is a muscle located in the forearm that plays a crucial role in the pronation of the forearm, which is the action of rotating the palm downward or facing backwards. Its distal attachment is critical for its function. The correct distal attachment of the pronator teres is at the middle of the lateral surface of the radius.

This location allows the muscle to effectively exert its force on the radius, facilitating efficient pronation. The muscle originates from the medial epicondyle of the humerus and the coronoid process of the ulna, but its insertion on the radius is what enables the rotational movement. Understanding the anatomy of the pronator teres and its attachment points helps in appreciating its role in forearm movements and overall upper limb function.

The other options include attachment points that do not represent the insertion of the pronator teres, thereby clarifying its specific anatomical function and relevance in movement.