Dermatomes : Mnemonic

Note: C1 doesn’t have a sensory branch

For the purpose of making learning easier, we divide the remaining dermatomal segments into 4 groups which will be accompanied by analogies and mnemonics.

dermatome map
Grant, John Charles Boileau, Public domain, via Wikimedia Commons

C2-C4

These supply the “hooded cape” region.

  • C2: hood region abutting the trigeminal distribution
  • C3: upper neck
  • C4: lower neck and shoulders

C5-T1

Dermatome C7 extends to the middle finger and divides dermatomes C5 and C6 (lateral) from C8 through T1 (medial).

  • C5: lateral aspect of arm
  • C6: lateral aspect of forearm and hand
  • C7: middle finger and ray
  • C8: medial aspect of hand
  • T1: medial aspect of forearm

T2-L1

These are present over the trunk and progresses sequentially from top to bottom. Remembering important landmarks is helpful.

  • T4: nipples
  • T10: umbilicus (0 looks like umbilicus)
  • L1: inguinal area

S2-S5

2, 3, 4, 5, stand on S1, lie on S2, sit on S3, wipe S4/S5

  • Slap thigh lateral then medial: L2 then L3
  • Slap lower legs medial then lateral: L4 then L5
  • Stand on sole of foot: S1
  • Lie on back of thigh and calf: S2
  • Sit on buttocks: S3
  • Wipe perianal area: S4, S5

Also note that: L5 is for Large toe and S1 is for Small toe


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