Which muscle runs the length of the forearm but does not cross the wrist joint?

Which muscle runs the length of the forearm but does not cross the wrist joint?

• A. Brachioradialis
• B. Flexor carpi radialis
• C. Extensor digitorum
• D. Pronator teres

Answer: (A)

The main idea is identifying a forearm muscle that travels along the entire forearm without crossing the wrist joint. Brachioradialis fits this description: it starts high on the humerus near the lateral supracondylar ridge and travels down the lateral forearm to insert on the radial styloid close to the wrist. Its tendon stays distal to the wrist, so the muscle does not cross the wrist joint, even though it crosses the elbow. This long, superficial muscle is primarily involved in elbow flexion, especially when the forearm is in a mid-position between pronation and supination. In contrast, muscles like flexor carpi radialis and extensor digitorum send tendons across the wrist to reach the hand, so they cross the wrist joint, and pronator teres, while not crossing the wrist, doesn’t run the full length of the forearm.

The main idea is identifying a forearm muscle that travels along the entire forearm without crossing the wrist joint. Brachioradialis fits this description: it starts high on the humerus near the lateral supracondylar ridge and travels down the lateral forearm to insert on the radial styloid close to the wrist. Its tendon stays distal to the wrist, so the muscle does not cross the wrist joint, even though it crosses the elbow. This long, superficial muscle is primarily involved in elbow flexion, especially when the forearm is in a mid-position between pronation and supination. In contrast, muscles like flexor carpi radialis and extensor digitorum send tendons across the wrist to reach the hand, so they cross the wrist joint, and pronator teres, while not crossing the wrist, doesn’t run the full length of the forearm.