A dermatome is an area of skin supplied predominantly by sensory fibres from one spinal nerve root. The territories overlap and vary between people, so the distribution of numbness, tingling, pain or rash can suggest levels to examine but cannot establish a diagnosis by itself.
This reference distinguishes the 28 standardized key sensory points tested on each side in the 2026 International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) from broader, approximate dermatome territories. It shows the ten ISNCSCI key muscle functions only at C5–T1 and L2–S1; reflexes are listed separately as non-ISNCSCI clinical correlations.
Zdrovia: https://www.zdrovia.ca/resources/dermatome-map/
Dermatome Reference
Spinal Level & Dermatome Lookup
Select a level for its 2026 ISNCSCI key sensory point, approximate cutaneous distribution, standardized key muscle function and common reflex correlation.
ISNCSCI tests 28 key sensory points on each side from C2 through the combined S4–5 point; it has no C1 sensory test point.
Start from the symptoms instead
Level C6
Upper limb2026 ISNCSCI key sensory point
Dorsal surface of the proximal phalanx of the thumb
A standardized bilateral examination landmark, not the full dermatome boundary
Approximate cutaneous distribution
Lateral forearm and thumb
Territories overlap and vary between people and published maps
ISNCSCI key muscle function
Wrist extensors
Common DTR correlation
Brachioradialis (mainly C5–C6)
Deep tendon reflexes are supportive correlations, not part of the ISNCSCI score, and commonly span more than one root.
These results are estimates based on published clinical data and are for informational purposes only. They do not constitute medical advice, a diagnosis, or a treatment recommendation. Interpret results with a qualified healthcare professional and alongside a comprehensive clinical assessment.
Zdrovia's smart blocks drop a dermatome finding straight into the chart note, so the sensory level is documented while you're still with the patient. See how smart blocks work →
Document the level you just mapped
Zdrovia's smart blocks drop a dermatome finding straight into the chart note, so the sensory level is documented while you're still with the patient.
How to use a dermatome map in assessment
Dermatomes are most useful for forming a localisation hypothesis, not making a diagnosis. For example, symptoms around the thumb and lateral forearm can suggest C6, while symptoms around the little finger can suggest C8, but median, ulnar or other peripheral nerve disorders may produce overlapping complaints. Corroborate the pattern with strength, reflexes and the rest of the neurologic examination.
Dermatome boundaries are not precise borders. Adjacent territories overlap substantially, individuals vary, and published maps disagree, particularly over the limbs, because they were derived using different populations and methods.
ISNCSCI therefore examines a reproducible key point for light touch and pin prick in each of 28 bilateral segments from C2 through the combined S4–5 point. These points standardize spinal cord injury examination; they are not a complete map of each root's cutaneous territory and should not be used alone to diagnose radiculopathy.
Dermatomes and shingles
According to the CDC, herpes zoster usually causes a unilateral rash in one or two adjacent dermatomes and usually does not cross the body's midline. The trunk along a thoracic dermatome and the face are common sites. The appearance is often clinically distinctive once vesicles develop, but other conditions can resemble it and atypical presentations may need laboratory confirmation.
Lesions outside the primary or adjacent dermatomes can occur, and disseminated or generalized disease is more likely in people who are immunocompromised. Facial or eye-area involvement, neurologic symptoms, immunosuppression or a widespread eruption warrants prompt clinical assessment rather than localization with this map alone.
Dermatomes vs. myotomes vs. peripheral nerves
A dermatome describes cutaneous sensation associated with a spinal root; a myotome describes muscle functions associated with a root. A named peripheral nerve contains fibres from multiple roots, so its sensory territory follows a different map, although overlap and anatomic variation mean real presentations do not always follow either chart neatly.
The distinction can guide an examination. Symptoms in the thumb, index and middle fingers may suggest median neuropathy, while involvement extending into the lateral forearm may support examining the C6 root and other causes. Distribution alone does not settle the diagnosis; provocative testing, motor findings, reflexes and electrodiagnostic or imaging studies may be needed depending on the presentation.