Upper Extremity Dermatomes & Myotomes

Dermatome
Location
C1&C2
Top of the skull
C3
Temporal bones
C4
Sides of the neck
C5
Base of the neck out to the tips of the shoulders (acromion process)
C6
Lateral Humerus down to the thumb
C7
Mid forearm to middle finger
C8
Medial forearm to fifth finger
T1
Medial Humerus


Myotome
Action
C1&C2
Neck flexion
C3
Lateral neck flexion
C4
Shoulder shrugging
C5
Shoulder abduction
C6
Elbow extension and wrist flexion
C7
Elbow flexion and wrist extension
C8
Thumb abduction and ulnar deviation
T1
Finger abduction and adduction

Lower Extremity Dermatomes & Myotomes

Dermatome
Location
L1
Superior portion of thigh
L2
Mid portion of the thigh
L3
Inferior portion of thigh to medial lower leg
L4
Distal lower leg down to the first toe
L5
Lateral foot up the lateral lower leg
S1
Achilles tendon


Myotome
Action
L1&L2
Hip Flexion
L3
Knee Extension
L4
Dorsiflexion of the foot
L5
1st toe extension
S1
Plantarflexion of the foot
S2
Knee flexion