How to diagnose cervical radiculopathy
Painful compression of a nerve root in the neck is known as cervical radiculopathy. The pain can be extreme, and the syndrome is often associated with an array of neurological signs and symptoms.
Cervical radiculopathy is commonly caused by an intervertebral disc fragment prolapsing onto a nerve root and causing irritation. Overgrown bone in a nerve root region may also precipitate an identical syndrome.
Compression of a nerve root may be totally asymptomatic, which is a very common occurrence. If you were to acquire magnetic resonance imaging (MRI) of your patient’s neck, you may find multiple areas of nerve root compression and perhaps even some stenosis—all without symptoms. Compression is a normal part of aging, but radiculopathy occurs when the nerve root becomes irritated from the compression and signals the brain that all is not well.
Remember that nerve roots carry both motor and sensory fibers, so compression can result in both motor and sensory symptoms. Motor and sensory findings should correspond to the specific nerve root that is irritated.
What should you do if you suspect cervical radiculopathy?
Follow three standard steps when evaluating a patient for cervical radiculopathy:
- Obtain a thorough history and record signs and symptoms
- Check the range of motion
- Perform a neurological exam
Obtain a thorough history and record signs and symptoms
Begin by obtaining a thorough history of the patient. Record the duration and nature of symptoms and treatments that have been attempted so far, and be alert for red flag conditions.
There are several common sensory presentations seen in patients with cervical radiculopathy:
- Severe pain radiating from the neck down the arm
- Intrascapular pain
- Paresthesia and dysesthesia in a dermatome pattern
In typical cervical radiculopathy, the patient will develop fairly severe radiating pain that runs from the neck and down the arm. The onset can be sudden or progressive over days or weeks. The pain can be extreme and of a sharp, deep, aching, or burning character.
This arm pain generally follows a pattern that can be tied to the distribution of the corresponding, compressed nerve root. However, the pain often becomes generalized to the entire arm or the bones of the arm and hand.
Nerves carry messages about pain from the periphery to the brain, so irritated nerves can give the brain all sorts of bad information. Any sort of painful scenario can be reproduced; the patient may feel like their arm is on fire, is being chopped up, or nails are being driven into it.
Alongside the radiating arm pain, intrascapular pain is quite common. Severe pain is usually accompanied by other sensory symptoms. Paresthesia and dysesthesia findings can include reports of prickly, tingling, or crawling sensations.
Any sensory symptoms should present in a dermatomal pattern. In other words, the pain should radiate into the dermatome of the affected nerve root. However, patients tend to generalize the region of pain and paresthesia beyond the defined dermatomes, so don’t let that mislead you!
Check range of motion
When evaluating a patient for cervical radiculopathy, check neck and shoulder range of motion. It is not uncommon to see dislocated and fractured shoulders misdiagnosed as cervical radiculopathy!
Perform a neurological exam
Perform a focused neurological exam—but don’t neglect a quick brain and cranial nerve evaluation. Do a detailed examination of upper extremity motor and sensory function as well as a reflex exam.
When evaluating the patient’s motor function, remember that nerve root compression causes lower motor neuron findings. Lower motor neurons extend from the anterior horn cells in the spinal cord out through the nerve roots. Then, the neurons join with fibers from other nerve roots to form a peripheral nerve that innervates a specific muscle or muscle group.
Motor function findings
Damage to lower motor neurons generally results in weakness, decreased tone, eventual atrophy of the innervated muscles, and sometimes loss of a deep tendon reflex.
The involved muscles can also show visible spontaneous twitching, known as fasciculations. Note that motor deficits are often subtle, and patients may be unaware of them until you find the deficits during an exam. However, some patients will have no definitive motor or sensory deficits.
So, in your evaluation, look for lower motor neuron findings in the arms. Make sure to check the legs as well, but in true cervical radiculopathy, leg function should not be affected.
Motor function testing considerations
Some patients will give you very poor effort throughout the affected arm upon testing. You may interpret this as weakness in multiple muscle groups, but multiple muscle groups should not be weak in cervical radiculopathy. Only the muscle groups innervated by the affected nerve root should show any signs of weakness.
The reason why some patients present with weakness in multiple muscle groups of the arm is because they are simply averse to pain and are subconsciously protecting themselves. A good motor exam can usually be obtained by repeated encouragement of the patient to engage the requested muscle groups. Be patient and remember how much pain they are in.
Sensory function findings
Your neurological exam should include checking pinprick and light touch sensation throughout the body—particularly in the affected arm. Sensory loss is often generalized by the patient. But in bonafide radiculopathy, the sensory loss follows a dermatomal pattern.
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How to differentiate between cervical radiculopathy and cervical myelopathy
As you build a case for cervical radiculopathy, always be suspicious of potential spinal cord compression and resulting myelopathy. Missing myelopathy could put a patient's neurological function in serious jeopardy.
In contrast to radiculopathies (which present with lower motor neuron signs), cervical myelopathies involve damage to upper motor neurons. Upper motor neuronal damage results in hypertonia, hyperreflexia, and late loss of strength (particularly in the lower extremities). Oftentimes, a Babinski sign can also be elicited.
Cervical myelopathy often presents with spinal cord sensory findings such as sensory levels in the trunk, loss of proprioception, and loss of balance. None of these findings should be seen in radiculopathy.
How to identify the affected nerve root in cervical radiculopathy
Once you’ve determined that your patient has radiculopathy, you’ll need to identify which nerve root is affected. Remember that there are seven cervical nerve roots (C2–C8). Cervical nerve roots exit the spine above the vertebrae with the corresponding name. So, the nerve root for C4 exits between the third and fourth cervical vertebrae (C3 and C4). The C8 nerve root, which exits above T1, is the exception to this rule.
Now, let’s dive into signs and symptoms that are common when nerve roots C4, C5, C6, C7, and C8 are affected by radiculopathy.
Signs and symptoms of C4 radiculopathy
Irritation of the C4 nerve root is unusual, but if present it may cause neck pain and paresthesia with no arm pain, major muscle, or reflex findings.
Signs and symptoms of C5 radiculopathy
Irritation of the C5 nerve root will cause pain and loss of sensation in the shoulder region alongside weakness in the deltoid muscle (which is responsible for shoulder abduction). The deltoid reflex may be diminished, but this isn’t the easiest reflex to elicit.
Signs and symptoms of C6 radiculopathy
Irritation of the C6 nerve root will cause pain and numbness down the arm and into the thumb. The biceps may be weak, and the biceps reflex will be diminished.
Signs and symptoms of C7 radiculopathy
Irritation of the C7 nerve root will cause pain and numbness down the arm and into the second and third fingers. The triceps may be weak, and the triceps reflex will be diminished.
Signs and symptoms of C8 radiculopathy
Irritation of C8 will cause arm pain and paresthesia down the arm into the fourth and fifth fingers as well as hand weakness. You should not find any associated reflex changes.
Now you should be better equipped to recognize and differentiate cervical radiculopathy from myelopathy—which is very important for your patients. You should also be more familiar with how to determine the affected nerve root, which will empower you to proceed to the next step—managing your patient’s cervical radiculopathy.
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- Devlin, VJ. 2012. Spine Secrets Plus. 2nd edition. Missouri: Mosby.
- Kaiser, M, Haid, R, Shaffrey, C, et al. 2019. Degenerative Cervical Myelopathy and Radiculopathy: Treatment Approaches and Options. Switzerland: Springer International Publishing.
- Louis, ED, Mayer, SA, and Rowland, LP. 2015. Merritt’s Neurology. 13th edition. Philadelphia: Wolters Kluwer.