Forget
There are some things in life which I just can’t memorize and dermatomal/myotomal maps are one of them. Weird cases of peripheral neurologic symptoms have presented to the ED in the setting of trauma and no trauma. So purely for selfish reasons, I’m making my own map to have on file.

This installment of the Paucis Verbis (In a Few Words) e-card series reviews Sensory and Motor Function Testing by Levels.

Testing Sensory Function by Level

dermatomes

Testing Motor Function by Level

  • C1-C4 Spontaneous breathing
  • C5 Shoulder abduction (deltoid)
  • C6 Wrist extension (carpi radialis longus and brevis)
  • C7 Elbow extension (triceps)
  • C8 Finger flexion (flexor digitorum superficialis/profundis, lumbricals)
  • T1 Finger adduction & abduction (dorsal/palmar interossei, abductor digiti quinti)
  • T1-T12 Intercostal and abdominal muscles
  • T12-L3 Hip flexion (iliopsoas)
  • L2-L4 Hip flexion, knee extension (quadriceps), hip adduction
  • L4 Ankle dorsiflexion and inversion (anterior tibialis)
  • L5 Big toe extension (ext hallucis longus), heel walk (ext digitorum), hip abduction (gluteus medius)
  • S1 Ankle plantarflexion and eversion (peroneus longus), toe walk (peroneus brevis), hip extension (gluteus maximus)
  • S2-S4 Rectal sphincter tone

Go to the ALiEM Cards site for more resources.
Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD

@M_Lin

Professor of Emerg Med at UCSF-Zuckerberg San Francisco General. Founder of ALiEM @aliemteam #PostitPearls https://t.co/7v7cgJqNEn
Michelle Lin, MD