Which pattern most strongly indicates a peripheral neuropathy?

• A. Dermatomal pattern with reflex changes
• B. Myotomal pattern of weakness
• C. Patchy involvement across several dermatomes
• D. Nerve-specific deficits within a single peripheral nerve distribution

Answer: (D)

A pattern where deficits are confined to the distribution of a single peripheral nerve points to a lesion at the nerve itself, which is characteristic of a peripheral neuropathy. In this scenario you’d expect sensory loss in the nerve’s specific distribution and weakness of the muscles it supplies, sometimes with reduced reflexes in that nerve’s reflex arc. This focal, nerve-specific involvement distinguishes a peripheral neuropathy from radiculopathy or plexopathy.

Radiculopathy, by contrast, follows a dermatomal (root-innervation) pattern and often shows corresponding changes in reflexes tied to a spinal level. Weakness that follows a myotomal distribution likewise points to a nerve root problem rather than a peripheral nerve. Involvement across several dermatomes or patchy spread suggests multiple roots or a broader process affecting several nerves, rather than a single peripheral nerve.