Which nerve innervates the extensor carpi radialis?

Which nerve innervates the extensor carpi radialis?

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

Answer: (B)

Extensor carpi radialis is a muscle of the forearm’s posterior compartment, so it is innervated by the radial nerve. The radial nerve supplies the extensor group, with extensor carpi radialis longus receiving input from the nerve before it divides and extensor carpi radialis brevis via the deep branch (posterior interosseous). In contrast, the other nerves serve different regions: the ulnar nerve mainly handles hand intrinsic muscles and some forearm flexors, the median nerve supplies most of the forearm flexors and some hand muscles, and the axillary nerve innervates the deltoid and teres minor. Therefore, the radial nerve is responsible for innervating the extensor carpi radialis.

Extensor carpi radialis is a muscle of the forearm’s posterior compartment, so it is innervated by the radial nerve. The radial nerve supplies the extensor group, with extensor carpi radialis longus receiving input from the nerve before it divides and extensor carpi radialis brevis via the deep branch (posterior interosseous). In contrast, the other nerves serve different regions: the ulnar nerve mainly handles hand intrinsic muscles and some forearm flexors, the median nerve supplies most of the forearm flexors and some hand muscles, and the axillary nerve innervates the deltoid and teres minor. Therefore, the radial nerve is responsible for innervating the extensor carpi radialis.