The upper limb is supplied from the C4 to T1 nerve roots. Occasionally T2 is also involved (Fig 1).
The dermatomes of the upper body are as shown, and each of the roots can readily be assessed (Fig 2).
Fig 1.
Fig 2. Upper body dermatomes (courtesy of Gecko Graphics)
The myotomes are as follows:
Fig 3. Shoulder joint – C4-5 Abduction
Fig 4. Shoulder joint – C7 Abduction
Fig 5. Elbow joint – C5-6 Flexion
Fig 6. Elbow joint – C7-8 Extension
Fig 7. Elbow joint – C6 Pronation/supination
Fig 8.Wrist joint – C6-7 Flexion
Fig. 9 Wrist joint – C6-7 Extension
Fig. 10 Fingers – T1 Abduction/adduction