**Core Concept**
The thenar muscles of the hand are a group of intrinsic muscles responsible for thumb movement, including flexion, extension, abduction, and opposition. These muscles are innervated by branches of the median nerve and the radial nerve.

**Why the Correct Answer is Right**
The thenar muscles, specifically the opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis, are supplied by the recurrent branch of the median nerve. This branch arises from the median nerve and provides motor innervation to these muscles, enabling precise thumb movements. The median nerve also provides sensory innervation to the thenar eminence.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the thenar muscles, specifically the opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis, are indeed supplied by the median nerve.
**Option B:** This option is incorrect because the radial nerve does supply the extensor pollicis brevis and abductor pollicis longus muscles, but not the thenar muscles.
**Option C:** This option is incorrect because the ulnar nerve supplies the third and fourth lumbricals, the interosseous muscles, and the hypothenar muscles, but not the thenar muscles.

**Clinical Pearl / High-Yield Fact**
The thenar muscles are responsible for fine motor movements of the thumb, and their dysfunction can lead to difficulties with activities such as buttoning shirts or tying shoelaces.

**Correct Answer: B. The radial nerve supplies the extensor pollicis brevis and abductor pollicis longus muscles, but not the thenar muscles.**