Nerve Root Map

Read each root's key point from C2 down to S5 with the labels on, then find all 28 rings.

Nerve Root Map

Name Date

Tap any dermatome to read, rename or leave it out

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
More options

Write the name of each numbered dermatome.Answer key

  1. C2
  2. C3
  3. C4
  4. C5
  5. C6
  6. C7
  7. C8
  8. T1
  9. T2
  10. T3
  11. T4
  12. T5
  13. T6
  14. T7
  15. T8
  16. T9
  17. T10
  18. T11
  19. T12
  20. L1
  21. L2
  22. L3
  23. L4
  24. L5
  25. S1
  26. S2
  27. S3
  28. S4 and S5

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a dermatome is answered.

Next step Next: a mixed quiz in chapter order

All 28 dermatomes on the diagram

Show the list

Front of the body: 20 rings 20

  1. C3 Key point: the hollow above the collarbone, the supraclavicular fossa. On the midclavicular line.
  2. C4 Key point: over the acromioclavicular joint. There the collarbone meets the shoulder blade at the tip of the shoulder.
  3. C5 Key point: the lateral (radial) side of the elbow crease (antecubital fossa). Just above the joint.
  4. T1 Key point: the medial (ulnar) side of the elbow crease (antecubital fossa). Beside the humerus's medial epicondyle.
  5. T2 Key point: the apex of the axilla, the top of the armpit. From here down to the groin the bands lie across the trunk, one under the next.
  6. T3 Key point: the third intercostal space, on the midclavicular line.
  7. T4 Key point: the fourth intercostal space, on the midclavicular line.
  8. T5 Key point: the fifth intercostal space, on the midclavicular line. Midway between the levels of T4 and T6.
  9. T6 Key point: the midclavicular line level with the xiphisternum. That is the lower tip of the breastbone.
  10. T7 Key point: one quarter of the way from xiphisternum to navel. On the midclavicular line.
  11. T8 Key point: the midclavicular line, halfway from the xiphisternum to the navel.
  12. T9 Key point: three quarters of the way from xiphisternum to navel. On the midclavicular line.
  13. T10 Key point: the midclavicular line at the level of the navel (umbilicus).
  14. T11 Key point: midway between the navel and the inguinal ligament. On the midclavicular line.
  15. T12 Key point: the inguinal ligament's midpoint. In the fold of the groin.
  16. L1 Key point: midway between the key points of T12 and L2. At the top of the thigh.
  17. L2 Key point: the front and inner thigh. Halfway along a line from the midpoint of the inguinal ligament to the medial femoral condyle.
  18. L3 Key point: the medial femoral condyle. The inner knob of the thigh bone just above the knee.
  19. L4 Key point: over the medial malleolus. The bump on the inner side of the ankle.
  20. L5 Key point: the foot's top (dorsum), at metatarsophalangeal joint three, where the third toe begins.

Back and hand: 8 rings 8

  1. C2 Key point: the back of the head. At least 1 cm to the side of the occipital protuberance, the bump at the base of the skull. C1 above it has no dermatome.
  2. C6 Key point: the back of the thumb, over its proximal phalanx. That is the bone nearest the knuckle.
  3. C7 Key point: the back of the middle finger, over its proximal phalanx.
  4. C8 Key point: the back of the little finger, over its proximal phalanx. C8 is the last of the eight cervical roots, and the numbering turns back up the arm with T1.
  5. S1 Key point: the lateral side of the calcaneus. The outer side of the heel bone.
  6. S2 Key point: the popliteal fossa's midpoint. The hollow at the back of the knee.
  7. S3 Key point: over the ischial tuberosity, the sitting bone. Or the fold under the buttock.
  8. S4 and S5 Key point: the perianal area. Less than 1 cm from the edge of the anus. The ASIA worksheet lists S4 and S5 together as one area.

How this list was compiled: Every ring sits on a key sensory point, and every point and detail line was checked again on 2026-09-30 against sources read that day. The wording is our own. The map followed is the list of key sensory points of the American Spinal Injury Association: International Standards for the Classification of Spinal Cord Injury, Key Sensory Points, June 2008, https://asia-spinalinjury.org/wp-content/uploads/2016/02/Key_Sensory_Points.pdf (one point for each level from C2 to S4-5, with S4 and S5 as one area; every point in this dataset is worded from it). Second source for the regions: Kenhub, Dermatomes, https://www.kenhub.com/en/library/anatomy/dermatomes (its own account of the two published maps, Keegan and Garrett 1948 and Foerster 1933, where they differ, and the landmarks that stay the same on both: C2 at the occipital protuberance, C3 the supraclavicular fossa, C4 the shoulder, C5 the outer arm, C6 the thumb, C7 the middle finger, C8 the little finger, T1 the inner arm, T2 the axilla, T4 to T12 down the trunk with T10 at the navel, L1 the groin, L2 and L3 the front of the thigh to the knee, L4 the inner ankle, L5 the top of the foot, S1 the heel and outer edge of the foot, S2 the back of the knee, S3 the buttock, S4 and S5 round the anus). Every ring of this dataset sits where both agree. Wikipedia, Dermatome (anatomy), https://en.wikipedia.org/wiki/Dermatome_(anatomy) (the definition; C1 has no dermatome; 8 cervical, 12 thoracic, 5 lumbar and 5 sacral nerves; bands across the trunk and lengthwise on the limbs; the exact areas as individual as fingerprints; its landmark list cites the same ASIA document, so it is not counted as a second source for the points). TeachMeAnatomy, Dermatomes, https://teachmeanatomy.info/the-basics/embryology/dermatomes/ (the two maps; the Foerster map is the one used with the ASIA scale). The bands drawn between the points are a plain schematic of the Foerster pattern as Kenhub describes it (C4 over the shoulder with T2 next below it on the chest; C5, C6 down the thumb side of the arm, T2, T1, C8 down the other side, C7 the middle of the hand and the back of the forearm; level bands T2 to T12, dipping toward the groin in front and sloping down and out from the spine behind; L2 and L3 on the front of the thigh, L4 inner and L5 outer leg, S1 the heel and outer foot, S2 the back of the thigh and calf, S3 and S4-5 at the midline of the buttocks). Where ASIA words a point more narrowly than the other sources (T1 just proximal to the medial epicondyle, where Wikipedia has just distal), the detail line keeps to what they share. This site is not affiliated with the American Spinal Injury Association, and nothing from its examination or grading rules is used. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry. The rings follow the key sensory points of the American Spinal Injury Association (June 2008); the bands are a plain schematic of the Foerster pattern and their dashed edges are not exact. No published figure was traced or copied. Licence: own work

How it works

Each band of skin on this nerve root map is a dermatome, the area one spinal nerve root supplies. Front and back views carry 28 numbered rings, each on the key point of a root from C2 to S5.

Read the full guide

Bands across the trunk, stripes along the limbs

On the trunk the dermatomes are bands, one under the next, from T2 in the armpit to T12 in the groin. The ten rings from T3 down swap sides to stay apart. On the limbs the bands run lengthwise: C5 to C8 go down the outer arm to the fingers, and T1 comes back up the inner arm. Lumbar points run down the front of the leg; sacral points climb the back, heel to buttock.

Seven landmarks to learn first

C6 is the thumb, C7 the middle finger, C8 the little finger. T10 is level with the navel. L4 is the inner ankle, L5 the top of the foot, S1 the outer heel. You can find all seven on your own body without counting ribs.

  • Of 30 roots from C1 to S5, C1 has no skin area and S4 and S5 share a ring: 28 rings.
  • The three finger rings are on an enlarged back of the hand, beside the back view.
  • For a short round pick Landmarks, 7 dermatomes. Print blank puts both views on one sheet.

Questions and answers

What is a dermatome?

An area of skin supplied mainly by the sensory fibers of one spinal nerve root. A dermatome map draws those areas as bands on the body and names each band after its root, such as C6 or L4.

Which dermatome map does this page follow?

The key sensory points published by the American Spinal Injury Association, one for each root from C2 to S4-5. The dashed bands between them are a plain sketch of the Foerster pattern: published maps differ, and the exact areas are as individual as fingerprints.

Why is there no C1 on a dermatome map?

The first cervical nerve has no dermatome, so the numbering of the skin starts with C2 on the back of the head. The face has no ring either: its skin belongs to the three branches of the trigeminal nerve, a cranial nerve.

Which dermatome is the belly button?

T10. Its key point is level with the navel. Higher up, T6 is level with the lower tip of the breastbone, and T7, T8 and T9 sit a quarter, a half and three quarters of the way down from there to the navel.

More quizzes

Show 7 more

Browse Human Body Quizzes