Execution
- 1Expose both lower limbs sufficiently for side-to-side sensory comparison.
- 2Test light touch and / or pinprick over lower-limb dermatomes.
- 3Check representative regions including lateral thigh L2-L3, anteromedial knee L3, medial leg L4, lateral leg and dorsum of foot L5, lateral foot S1, and posteromedial thigh S2.
- 4Ask whether sensation feels normal, reduced, increased, painful, or altered compared with the opposite side.
- 5Map findings and compare the pattern with myotomes, reflexes, and nerve tension tests.
Positive outcome
Reduced, absent, painful, or clearly altered sensation in a dermatomal distribution is positive. Non-dermatomal or inconsistent sensory loss should be interpreted cautiously. Dermatomal overlap is common, so the pattern matters more than a single point.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Tawa et al. (2017) — systematic review | NA | 61 | 63 | 1.65 | 0.62 |
| Zale et al. (2023) — systematic review | NA | NA | NA | NA | NA |
CommentDermatome testing is useful for localization but weak for confirming lumbar radiculopathy because dermatomes overlap and individual maps vary. Recent reviews challenge the accuracy of sensory loss for exact root localization. Use sensory findings as one part of the neurological pattern.
Low Clinical Value