Mnemonic

Thoracic Dermatome Landmarks

A mnemonic for the key dermatome levels on the trunk.

Expansion

T4 at the nipple, T6 at the xiphoid, T10 at the umbilicus, L1 at the groin

Expansion

  • T2 - the angle of Louis and the medial arm
  • T4 - the nipple (T4 at the teat)
  • T6 - the xiphoid process
  • T8 - the lower costal margin
  • T10 - the umbilicus (T10 at the belly button)
  • T12 and L1 - the groin and inguinal region

These are used to check the block height after spinal anaesthesia, to determine the level of a spinal cord lesion, and to interpret the distribution of shingles.

Remember that the thoracic dermatomes slope downwards and forwards as they pass round the trunk, so a posterior landmark corresponds to a lower level anteriorly.