Needle EMG · Core

Choose muscles that test localization

Hypothesis-driven muscle sampling

Each sampled muscle should answer a distinct anatomical question.

3 learning sectionsCompiled 2026-09-08English edition · Traditional Chinese available

01Build comparisons

  • Choose muscles sharing a myotome but supplied by different nerves, then muscles from the same nerve at different levels or myotomes.
  • Include proximal and distal sites according to the hypothesis; do not sample only the weakest muscle.

02Examples

  • Foot drop: after TA and fibularis longus, use tibialis posterior and TFL to test L5 outside the fibular distribution.
  • Hand intrinsic weakness: add EIP and appropriate proximal muscles to FDI/APB for a C8–T1 comparison.

03Adapt to limitations

  • Myotomal overlap, fascicular injury and prior surgery can alter expected patterns.
  • Verify muscle identification and safety, then adapt the study to the information obtained.

Pause and explain

Explain in your own words: “A muscle table helps form hypotheses; the examination still needs individual design.” Then think of a situation in which it could be misinterpreted.

Show a review prompt

More muscles from one nerve may not distinguish a root lesion from mononeuropathy.

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References and further reading

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.