Small muscles of hand are supplied by:

**Core Concept**
The small muscles of the hand are a group of intrinsic muscles responsible for fine motor movements and delicate manipulations. These muscles are innervated by specific branches of the peripheral nervous system, which are crucial for hand function and dexterity.

**Why the Correct Answer is Right**
The small muscles of the hand are primarily supplied by the ulnar nerve, specifically its deep branch, which provides motor innervation to the interosseous muscles, lumbricals, and the medial two digits (II and III). The ulnar nerve also carries sensory fibers from the little finger and the ulnar half of the ring finger. The motor supply to the small muscles of the hand is crucial for precise movements, grip strength, and finger dexterity.

**Why Each Wrong Option is Incorrect**
**Option A:** The median nerve primarily supplies the thenar muscles (thumb muscles) and the lateral two digits (I and II), making it an incorrect choice for the small muscles of the hand.
**Option B:** The radial nerve supplies the extensor muscles of the wrist and fingers, which are involved in finger extension rather than fine motor movements.
**Option C:** The musculocutaneous nerve supplies the biceps brachii and brachialis muscles in the arm, which are not involved in hand movements.

**Clinical Pearl / High-Yield Fact**
The ulnar nerve is particularly vulnerable to injury at the elbow, known as cubital tunnel syndrome, which can result in weakness and numbness of the hand, especially in the little finger and ring finger.

**Correct Answer: C. The ulnar nerve.**