Clinical localization · Advanced
Distinguish plexus and root lesions
Brachial & lumbosacral plexopathy
Combine sensory responses, muscles across nerves and paraspinal findings.
01Postganglionic clues
- Plexus lesions are postganglionic and may reduce corresponding SNAPs. Pure plexopathy generally spares paraspinals.
- Radiculoplexus neuropathy can involve both preganglionic and postganglionic structures and does not fit a simple binary rule.
02Upper limb
- Select LABC, MABC, radial, median and ulnar SNAPs according to trunk or cord hypotheses.
- Combine multiple terminal nerve muscles, considering trauma, tumor, radiation and neuralgic amyotrophy.
03Lower limb
- Use femoral, obturator, gluteal and sciatic territories to compare lumbar plexus, sacral plexus and sciatic lesions.
- Pain with patchy proximal weakness may suggest radiculoplexus neuropathy rather than one root.
Related nerves
Pause and explain
Explain in your own words: “Map the abnormalities first, then find the anatomical site that best explains them.” Then think of a situation in which it could be misinterpreted.
Show a review prompt
Normal paraspinals do not automatically prove plexopathy.
Check your understanding →
Progress stays in this browser. Marking a page as read is not a competency certification.
References and further reading
- Brachial Plexopathy: Differential Diagnosis and Treatment ↗AAPM&R KnowledgeNow · Society educational review · Link accessed 2026-09-08
- Lumbosacral Plexopathy and Sciatic Neuropathy ↗AAPM&R KnowledgeNow · Society educational review · Link accessed 2026-09-08
Educational synthesis; independent neuromuscular specialist review is pending. Publication dates and compilation dates are distinct. This is an original teaching synthesis; consult the source for complete methods and criteria.