A Brachial Plexus MRI is a specialized scan focused on the brachial plexus — a complex network of nerves that travels from the lower neck, through the shoulder, and into the arm. These nerves carry signals that allow you to move and feel your shoulder, arm, and hand.
Doctors request this scan when investigating weakness, numbness, pain, or paralysis affecting the shoulder, arm, or hand — especially when the cause is suspected to be a nerve injury rather than a problem in the muscle, joint, or bone.
Unlike X-rays or CT scans, a Brachial Plexus MRI shows the nerves themselves and any surrounding soft tissue, tumor, or scar that may be affecting them.
Why would my doctor ask for a Brachial Plexus MRI?
Your doctor may recommend this scan to look closely at the nerves of the shoulder and arm, especially if you have:
- Weakness or paralysis of the arm following a road traffic accident, fall, or shoulder dislocation.
- A baby with arm weakness or limited movement after a difficult delivery (a condition called brachial plexus birth injury, including Erb's palsy and Klumpke's palsy).
- Persistent burning pain or "electric shock" sensations in the shoulder, arm, or hand.
- Numbness or tingling that follows a specific pattern in the arm.
- A lump or mass in the neck or shoulder that could be pressing on the nerves.
- A history of cancer involving the breast, lung, or lymph nodes near the brachial plexus.
- Symptoms suggesting nerve compression by a tight muscle or extra rib (thoracic outlet syndrome).
- A planned nerve repair or transfer surgery, where detailed nerve mapping is essential.
What can a Brachial Plexus MRI detect?
A Brachial Plexus MRI helps doctors visualize:
- The full course of the brachial plexus nerves from the spinal cord to the upper arm.
- The roots, trunks, divisions, cords, and branches of the plexus.
- The muscles supplied by these nerves, and any signs of nerve-related muscle wasting.
- Surrounding soft tissues, blood vessels, and bones.
It is particularly useful for identifying:
- Nerve root avulsion (a nerve torn from the spinal cord) after a severe injury.
- Stretch injuries and other forms of nerve damage.
- Tumors of the nerves themselves (such as a schwannoma) or tumors pressing on the plexus.
- Scar tissue from previous injury or surgery.
- Inflammation of the nerves (brachial neuritis).
- An extra rib or tight band of tissue compressing the plexus.
Do I need any special preparation for a Brachial Plexus MRI?
In most cases, no special preparation is needed. However:
- Remove all jewelry, body piercings, hairpins, and clothing with metal zippers or buttons.
- Inform your doctor or radiographer of any implants, especially pacemakers, surgical metal from previous shoulder surgery, or cochlear implants.
- You can eat, drink, and take your usual medications normally.
- If contrast is planned, a recent kidney function test may be requested.
Will I be injected with dye for this scan?
Often, yes. Gadolinium contrast is frequently used to help highlight nerve tumors, inflamed nerves, or scar tissue. For some standard injury assessments, the scan can be performed without dye. Your radiologist will decide based on what the doctor is looking for.
What does a Brachial Plexus MRI feel like?
The scan is painless. You will lie flat on a padded table, usually on your back, with your arms positioned carefully — sometimes by your sides, sometimes raised above your head, depending on the scan technique used at your center.
A receiving device (a coil) will be placed over your neck and shoulder. You will hear loud knocking and humming sounds during the scan, and earplugs or headphones will be provided. The radiographer will be in contact with you throughout.
The scan can be uncomfortable if your shoulder is already painful or your range of motion is limited. Tell the radiographer in advance — they can adjust your position and add cushions to keep you as comfortable as possible.
Is it safe for pregnant women or children?
Yes. The scan uses no radiation. It is the preferred test for evaluating brachial plexus birth injuries in babies — though young infants usually need sedation or general anaesthesia to stay still long enough. Pregnant women should consult their doctor; contrast dye is usually avoided during pregnancy.
How long does a Brachial Plexus MRI take?
The scan usually takes 45 to 60 minutes. Because the brachial plexus is complex and the nerves are small, the imaging is more detailed than a standard shoulder or neck MRI, and takes longer.
When will I get my results?
After the scan, a Radiologist — often one with experience in nerve imaging — will carefully review the images and prepare a detailed report for your doctor. Results are typically ready within a few days. Your doctor will discuss the findings, and you may be referred to a neurologist, peripheral nerve surgeon, or hand surgeon depending on what is found.
How is this different from a neck MRI or a shoulder MRI?
A standard neck or shoulder MRI is set up to look at bones, discs, joints, and large soft tissues — not at the small, complex nerves of the brachial plexus. A Brachial Plexus MRI uses different settings and sequences specifically designed to highlight these nerves and their pathway. If your symptoms point to a nerve problem rather than a joint or disc problem, your doctor will request the brachial plexus protocol specifically.
What is Erb's palsy and can the scan show it?
Erb's palsy is a brachial plexus injury that happens during difficult childbirth, usually when there is excessive pulling on the baby's neck and shoulder during delivery (often with shoulder dystocia). The baby is born with a weak or paralysed arm on one side. A Brachial Plexus MRI can show exactly which nerves are affected and whether any have been torn from the spinal cord — information that helps the paediatric team decide whether the nerves are likely to recover on their own with physiotherapy, or whether surgery to repair them is needed. The scan is usually performed in the first few months of life, often under sedation or general anaesthesia.
Will the scan tell me whether my nerves will recover?
It gives strong clues but does not give a guaranteed prediction. The scan can show whether a nerve is torn completely (which has poor recovery prospects without surgery), stretched but intact (which often recovers gradually), or compressed by a tumor or scar (which may improve once the compression is relieved). Your doctor will combine the scan findings with your symptoms, the time since injury, and a clinical examination of nerve and muscle function. Recovery from nerve injury is slow — improvement is measured over months, not days — and a follow-up scan may be needed to track changes.
What if I'm nervous about being inside the scanner?
It is common to feel anxious, especially when the scan takes longer than usual or when your shoulder is already painful. The radiographer will be in contact with you the entire time through an intercom and you will hold a squeeze ball to alert them if you need a break. If you are very claustrophobic or unable to lie still due to pain, talk to your doctor about pain relief or a mild sedative before the scan.
Sources and further reading
Conclusion
A Brachial Plexus MRI is a safe, radiation-free, and highly detailed way to investigate weakness, numbness, or pain in the shoulder and arm caused by nerve problems. By showing the nerves themselves — not just the bones and muscles around them — it gives your doctor the information needed to plan recovery, physiotherapy, or surgery.