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Dermatomes Quiz

Twenty questions on the dermatome map: which spinal nerve root supplies each strip of skin. Front view on the left, back on the right. Dermatomes overlap and vary between people, so this is the classic textbook map. Tap an answer to see if you’re right.

  1. Question 1 of 20

    Which dermatome is highlighted, at the level of the nipple?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. T4
    2. T6
    3. T10
    4. T2
    Show answer

    Answer: T4. T4 at the nipple is the classic landmark. Handy rhyme: T4 at the teat pore.

  2. Question 2 of 20

    Which dermatome is highlighted, at the level of the navel?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. T12
    2. T8
    3. L1
    4. T10
    Show answer

    Answer: T10. T10 at the belly button: ‘T10 for the belly but-ten’.

  3. Question 3 of 20

    Which dermatome covers the highlighted thumb side of the hand?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. C8
    2. C6
    3. C7
    4. C5
    Show answer

    Answer: C6. Make a ‘6’ with your thumb and index finger to remember it.

  4. Question 4 of 20

    Which dermatome covers the highlighted little finger side of the hand?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. T1
    2. C7
    3. C8
    4. C6
    Show answer

    Answer: C8. C8 runs down the little finger and the edge of the hand.

  5. Question 5 of 20

    Which dermatome covers the highlighted middle finger?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. C8
    2. C5
    3. C7
    4. C6
    Show answer

    Answer: C7. C7 sits between them, over the middle finger.

  6. Question 6 of 20

    Which dermatome is highlighted, around the groin?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. L1
    2. L2
    3. T12
    4. S1
    Show answer

    Answer: L1. L1 covers the groin, just below where the trunk dermatomes end.

  7. Question 7 of 20

    Which dermatome covers the highlighted outer shoulder and upper arm?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. C6
    2. C4
    3. T1
    4. C5
    Show answer

    Answer: C5. C5 covers the ‘regimental badge’ area over the deltoid.

  8. Question 8 of 20

    Which dermatome is highlighted, over the top of the shoulders?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. T2
    2. C4
    3. C3
    4. C5
    Show answer

    Answer: C4. C4 sits like a cape over the shoulders, just above where T2 starts on the chest.

  9. Question 9 of 20

    Which dermatome is highlighted, at the back of the head?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. C3
    2. C2
    3. C1
    4. Trigeminal V1
    Show answer

    Answer: C2. C2 covers the back of the scalp. C1 usually has no skin area, and the face belongs to the trigeminal nerve.

  10. Question 10 of 20

    Which dermatome covers the highlighted inner forearm?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. T1
    2. T2
    3. C6
    4. C8
    Show answer

    Answer: T1. T1 runs along the inner (ulnar) side of the forearm and elbow.

  11. Question 11 of 20

    Which dermatome covers the highlighted front of the knee?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. L5
    2. L4
    3. L3
    4. L2
    Show answer

    Answer: L3. L3 crosses the front of the knee. L2 is the upper front thigh.

  12. Question 12 of 20

    Which dermatome covers the highlighted inner shin and ankle?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. L3
    2. S1
    3. L5
    4. L4
    Show answer

    Answer: L4. L4 runs down the inside of the leg to the inner ankle.

  13. Question 13 of 20

    Which dermatome covers the highlighted top of the foot and big toe?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. S1
    2. L5
    3. S2
    4. L4
    Show answer

    Answer: L5. L5 covers the outer shin and top of the foot. Test it on the web between the big toe and second toe.

  14. Question 14 of 20

    Which dermatome covers the highlighted outer foot and little toe?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. L5
    2. L4
    3. S2
    4. S1
    Show answer

    Answer: S1. S1 covers the outer edge and sole of the foot. The ankle jerk tests the same root.

  15. Question 15 of 20

    Which dermatome is highlighted, down the back of the thigh?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. S3
    2. L3
    3. S2
    4. S1
    Show answer

    Answer: S2. S2 runs in a strip down the back of the thigh and calf.

  16. Question 16 of 20

    A slipped disc between L4 and L5 usually squashes which nerve root?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. L5
    2. L4
    3. L3
    4. S1
    Show answer

    Answer: L5. Most disc bulges go slightly to the side and catch the root heading down to the next level. So an L4/5 disc hits L5: pain and numbness over the top of the foot.

  17. Question 17 of 20

    Shingles appears as a painful rash in one dermatome. Which region is most often affected?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. Thoracic (chest and trunk)
    2. Lumbar
    3. Sacral
    4. Cervical
    Show answer

    Answer: Thoracic (chest and trunk). More than half of shingles is thoracic: a band of blisters around one side of the trunk that stops at the midline.

  18. Question 18 of 20

    Numbness in the highlighted ‘saddle’ area with new bladder trouble suggests what?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. Pudendal nerve entrapment
    2. Cauda equina syndrome
    3. Sciatica only
    4. Shingles
    Show answer

    Answer: Cauda equina syndrome. S3 to S5 supply the saddle area. With back pain and bladder or bowel changes, it’s a surgical emergency.

  19. Question 19 of 20

    Irritation under the diaphragm often hurts at the shoulder tip, in the highlighted area. Why?

    FRONTBACKC5C6C7C8S1L2L3L4L5T4nippleT10navelL1groinC2C3C4S2S1S3–5
    Skin nerve-root map: front (patient’s right on your left) and back
    1. The diaphragm is made of shoulder muscle
    2. The vagus nerve supplies the shoulder
    3. The phrenic nerve shares roots C3 to C5
    4. The liver touches the shoulder
    Show answer

    Answer: The phrenic nerve shares roots C3 to C5. Pain from the diaphragm is felt in the C4 dermatome: referred pain. Think gallbladder, a ruptured ectopic pregnancy, or gas after keyhole surgery.

  20. Question 20 of 20

    Shingles on the tip of the nose (Hutchinson’s sign) warns of what?

    1. Spread to the spinal cord
    2. A C2 root problem
    3. Bell’s palsy
    4. Eye involvement from the trigeminal nerve (V1)
    Show answer

    Answer: Eye involvement from the trigeminal nerve (V1). The nasociliary branch of V1 supplies both the nose tip and the eye. Shingles here needs urgent eye review.

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Common questions

What is a dermatome?

A strip of skin supplied by one spinal nerve root. Mapping numbness or a shingles rash to a dermatome tells you which root is involved.

What are the key dermatome landmarks?

C6 thumb, C7 middle finger, C8 little finger, T4 nipple, T10 navel, L1 groin, L3 knee, L4 inner ankle, L5 top of the foot and big toe, S1 outer foot and little toe, S3 to S5 saddle area.

Why do dermatome maps differ between books?

Neighbouring dermatomes overlap a lot and vary between people, and older maps were made in different ways. The landmarks above are the ones most books agree on.

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Updated 16 November 2026. Diagrams are simplified, original sketches, not to scale. General education, not personal medical advice.