Overview
A dermatome is an area of skin that has sensory innervation from a given spinal nerve. A myotome is a group of muscles that a single spinal nerve innervates.
Dermatomes
Some dermatomes are as follows:
- C6: thumb
- C7: middle finger
- C8: little finger
- T1: anteromedial forearm and arm
- T4: nipple
- T6: xiphoid process
- T10: umbilicus (‘belly but-ten’)
- L3: medial knee
- L4: anterior knee and medial malleolus
- L5: dorsum of the foot and first, second, and third toes
- S1: lateral malleolus
- S2 and S3: genitalia
Myotomes
Some myotomes are as follows:
- C5: elbow flexors
- C6: wrist extensors
- C7: elbow extensors
- C8: finger flexors
- T1: finger abductors
- L2: hip flexors
- L3: knee extensors
- L4: ankle dorsiflexors
- L5: long toe extensors
- S1: ankle plantarflexors
