The triceps reflex is innervated by which nerve?

The triceps reflex is innervated by which nerve?

• A. Radial nerve
• B. Ulnar nerve
• C. Median nerve
• D. Musculocutaneous nerve

Answer: (A)

The triceps reflex tests the triceps brachii, the muscle that extends the elbow. This muscle is innervated by the radial nerve, which provides the motor signals needed for the elbow- extension response. When the tendon is tapped, the stretch triggers a reflex arc that travels through the radial nerve to the spinal cord and back to the triceps to produce elbow extension. The other nerves listed supply different muscles—for example, musculocutaneous to the forearm flexors like the biceps, median to most forearm flexors, and ulnar to some forearm and hand muscles—so they don’t control the triceps reflex.

The triceps reflex tests the triceps brachii, the muscle that extends the elbow. This muscle is innervated by the radial nerve, which provides the motor signals needed for the elbow- extension response. When the tendon is tapped, the stretch triggers a reflex arc that travels through the radial nerve to the spinal cord and back to the triceps to produce elbow extension. The other nerves listed supply different muscles—for example, musculocutaneous to the forearm flexors like the biceps, median to most forearm flexors, and ulnar to some forearm and hand muscles—so they don’t control the triceps reflex.