Which finding would most strongly suggest radiculopathy over peripheral neuropathy?

• A. Dermatomal/Myotomal weakness with reflex changes
• B. Isolated weakness in the abductor pollicis brevis
• C. Symmetric distal weakness
• D. Sensory loss in a single digit not following a dermatomal pattern

Answer: (A)

Radiculopathy comes from irritation or compression of a nerve root, so the deficits align with a specific dermatomal and myotomal distribution. When weakness is accompanied by reflex changes that map to the same root level, it strongly localizes to a nerve root rather than to a peripheral nerve or a diffuse neuropathy. This pattern—weakness that follows a dermatome or myotome and altered reflexes—signals root-level involvement.

In contrast, weakness isolated to a single hand muscle like the abductor pollicis brevis points to a focal peripheral nerve issue (in this case, a median nerve problem at the wrist or forearm) rather than a root problem. Symmetric distal weakness is typical of a polyneuropathy that affects many nerves in a length-dependent fashion, not one root. Sensory loss confined to a single digit without a dermatomal pattern is more consistent with a focal peripheral nerve or small-fiber neuropathy than with radiculopathy, which tends to follow a dermatomal map.

So the presence of dermatomal/myotomal weakness with reflex changes directly flags radiculopathy, distinguishing it from other patterns seen in peripheral nerve or diffuse neuropathic processes.