Which nerve innervates interossei and intrinsic hand muscles, enabling finger abduction and adduction, with sensation to little finger and medial half of the ring finger?

Which nerve innervates interossei and intrinsic hand muscles, enabling finger abduction and adduction, with sensation to little finger and medial half of the ring finger?

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

Answer: (A)

Finger abduction and adduction rely on the interossei, the intrinsic hand muscles that move the fingers toward or away from the middle finger. These muscles are innervated by the deep branch of the ulnar nerve, which provides motor supply to the interossei and most of the other intrinsic hand muscles. The same nerve also carries sensation to the little finger and the medial half of the ring finger, matching the described sensory distribution. The other nerves don’t cover both the interossei innervation and that specific sensory area: the median nerve mainly supplies lateral digits and some thenar muscles; the radial nerve covers the dorsum of the hand and forearm; the musculocutaneous nerve supplies the lateral forearm.

Finger abduction and adduction rely on the interossei, the intrinsic hand muscles that move the fingers toward or away from the middle finger. These muscles are innervated by the deep branch of the ulnar nerve, which provides motor supply to the interossei and most of the other intrinsic hand muscles. The same nerve also carries sensation to the little finger and the medial half of the ring finger, matching the described sensory distribution. The other nerves don’t cover both the interossei innervation and that specific sensory area: the median nerve mainly supplies lateral digits and some thenar muscles; the radial nerve covers the dorsum of the hand and forearm; the musculocutaneous nerve supplies the lateral forearm.