Adductor pollicis is supplied by
**Core Concept**
The **adductor pollicis** muscle is a key component of the thenar eminence, responsible for thumb movement. Its innervation is crucial for grasping and fine motor functions. The muscle is supplied by the **ulnar nerve**.
**Why the Correct Answer is Right**
The **ulnar nerve** is responsible for innervating several muscles in the hand, including the **adductor pollicis**. This nerve originates from the **brachial plexus** and runs down the arm to the hand, supplying various muscles and providing sensory innervation. The **ulnar nerve**'s involvement in thumb movement is essential for overall hand function.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not specified, but typically, the **median nerve** supplies muscles like the **thenar eminence** (except the **adductor pollicis**).
**Option B:** Incorrect as it is not provided, but usually, the **radial nerve** is involved in wrist and finger extension, not thumb adduction.
**Option D:** Incorrect, as the option is missing, but typically, other nerves like the **musculocutaneous nerve** are not involved in supplying the **adductor pollicis**.
**Clinical Pearl / High-Yield Fact**
The **ulnar nerve**'s supply to the **adductor pollicis** is critical for thumb function. Damage to this nerve can result in **claw hand** deformity and impaired fine motor skills.
**Correct Answer:** D. Ulnar nerve.