C7 Nerve root
| Level | Root | Pain & Sensory Change | Motor Weakness | Abnormal Reflexes |
|---|---|---|---|---|
| C4/C5 | C5 | Deltoid2 Lateral arm2 |
Deltoid2 Biceps2 |
Bicep reflex2 |
| C5/C6 | C6 | Radial forearm to thumb and index finger2 | Biceps2 Wrist extensor2 |
Bicep reflex2 Brachioradialis reflex2 |
| C6/C7 | C7 | Midradial forearm to index and middle finger2 | Wrist Flexor2 Tricep2 |
Triceps reflex2 |
| C7/T1 | C8 | Ulnar forearm to ring and little finger2 | Hand Intrinsic2 Finger Flexor2 |
N/a2 |
Motor Innervation
Dermatome
Lesion
“This nerve root is often compressed by disc herniation at the C6 C7 vertebral level (the most common level of disc herniation) [20,29]. C7 root involvement results in pain in the dorsal forearm. In some patients, pain may be subscapular or located in the deep breast or chest [24]. Sensory disturbances occur on the third and fourth digits. Paresis occurs variably in the following muscles: serratus anterior, pectoralis major, latissimus dorsi, pronator teres, flexor carpi radialis, triceps, extensor carpi radialis longus, extensor carpi radialis brevis, and extensor digitorum (examination of these muscles is described in Chapter 2 ). The triceps reflex (C7 C8) may be depressed.”3
“Pseudomyotonia is a term applied to the difficulty in opening the hand because of cervical osteoarthritis. Muscle relaxation is normal but attempts to extend the fingers produce paradoxical flexion of the fingers, probably as a result of misdirected regeneration of C7 nerve root fibers [34].”3
Examination
Muscle Strength
“The clinician asks the patient to place the arms out in front, with the elbows flexed slightly and the forearms, wrists, and fingers in neutral. The clinician applies an upward force to the palm of the patient’s hands (Fig. 25-28).”4