From the Research
To test dermatomal level in patients with a herniated nucleus pulposus, perform a systematic sensory examination using light touch and pinprick testing along specific dermatomes, as this approach is crucial for localizing the level of nerve root compression and guiding diagnosis and treatment planning. Begin by explaining the procedure to the patient, then use your fingertips or a cotton swab for light touch sensation and a safety pin or neurological pinwheel for pinprick sensation. Test bilaterally, comparing the affected side to the unaffected side, and proceed in a methodical pattern covering key dermatomes:
- C5 (lateral arm)
- C6 (thumb and index finger)
- C7 (middle finger)
- C8 (little finger)
- T4 (nipple level)
- T10 (umbilicus)
- L2 (anterior thigh)
- L3 (medial knee)
- L4 (medial ankle)
- L5 (dorsum of foot and big toe)
- S1 (lateral foot and little toe) Ask the patient to report any differences in sensation between sides, noting areas of numbness, tingling, or hypersensitivity. Document findings using a dermatome map for reference. This examination is supported by studies such as 1, which evaluated the validity of different clinical tests, including lumbar extension and slump test, in comparison with findings on computed tomography (CT) and/or magnetic resonance imaging (MRI) scan, highlighting the importance of a thorough physical and neurological examination in the evaluation of patients with suspected herniated nucleus pulposus. Combining dermatomal testing with motor strength assessment and reflex testing provides a comprehensive neurological evaluation that guides diagnosis and treatment planning for herniated nucleus pulposus, as emphasized in the context of managing sciatica due to herniated nucleus pulposus 2.