A helpful guide or refresher for learning about dermatomes and myotomes.
Dermatome map
Definition: “An area of skin supplied by a single spinal nerve”
Myotomes
Definition: “A group of muscles innervated by a single spinal nerve”
This list details some important myotomes’ nerve roots and the actions that their associated muscles produce:
C4 – shoulder shrugs
C5 – shoulder abduction and external rotation; elbow flexion
C6 – wrist extension
C7 – elbow extension and wrist flexion
C8 – thumb extension and finger flexion
T1 – finger abduction
L2 – hip flexion
L3 – knee extension
L4 – ankle dorsiflexion
L5 – great toe extension
S1 – ankle plantarflexion
S4 – bladder and rectum motor supply
Learn more
Dermatomes and myotomes Geeky Medics – a website designed for students and health professionals.