You got your MRI results back. The report says something about a herniated disc at C4-C5 or C5-C6, possibly with radiculopathy, possibly with foraminal narrowing, possibly with words you have never seen before and a tone that feels clinical and distant from the pain that has been radiating down your arm for the past three weeks. You came home from that appointment or opened that patient portal result and searched for exactly this, because what the report says and what your body is telling you have not yet been connected in a way that makes sense to you. That is what this is for.

The cervical spine, the portion of your spine that runs through your neck, is made up of seven vertebrae labeled C1 through C7. Between each pair of vertebrae sits an intervertebral disc, a structure with a tough fibrous outer ring called the annulus fibrosus and a soft, gel-like center called the nucleus pulposus. The disc functions as a shock absorber and as a spacer that keeps the vertebrae from grinding against each other and keeps the openings through which nerve roots exit the spine wide enough for those nerves to pass freely. When a disc herniates, the outer ring tears and the inner material pushes outward, sometimes pressing against a nerve root, sometimes pressing against the spinal cord itself, and sometimes doing both.

C4-C5 and C5-C6 are the two most commonly injured levels in car accidents, and they are not injured by coincidence. They sit at the point of maximum mechanical stress in the cervical spine during the kind of rapid flexion-extension motion that a collision produces. The levels above them are more constrained by the skull, the levels below are partially stabilized by the thoracic spine, but C4-C5 and C5-C6 bear the full brunt of the whipping force that occurs when your head lurches forward and snaps back faster than your muscles can respond. The discs at these levels were already under more daily mechanical stress than most people realize before the accident, and the trauma of the collision can push them past the point they were already approaching or blow through a disc that was otherwise perfectly healthy.

Here is the thing that will matter to you both medically and legally, and that almost no one explains clearly at the outset. The symptoms of a C4-C5 herniation and a C5-C6 herniation are different in specific, anatomically predictable ways, and knowing which pattern fits what you are experiencing tells you a great deal about which diagnosis is accurate and how the injury is likely to progress. At C4-C5, when the disc material compresses the C5 nerve root, the symptoms run to the shoulder and the outer part of the upper arm. People with C5 involvement describe weakness in the deltoid muscle, difficulty raising their arm to the side, and sometimes an aching numbness along the lateral shoulder. The bicep reflex may be diminished. If you have been noticing that your shoulder feels weak or that lifting your arm feels different than it used to, especially if the weakness is primarily in the deltoid rather than elsewhere in the arm, that is a C5 pattern.

At C5-C6, the compressed nerve root is C6, and C6 runs a more predictable and distinctive path. The numbness and tingling that accompany C6 compression travel down the lateral forearm and into the thumb and index finger. If you wake up at night with your thumb numb and have to shake your hand out to get the feeling back, that is a recognizable C6 symptom. Weakness in C6 injury shows up in the bicep and in the wrist extensors, the muscles responsible for bending the wrist back. The brachioradialis reflex, which your doctor tests by tapping the outer part of your forearm near the wrist, is the reflex most commonly diminished or absent in C6 injury. Many people with a C5-C6 herniation also describe a burning or electric quality to their symptoms, a sensation that feels fundamentally different from ordinary muscle soreness and that they often struggle to describe to their doctor in a way that conveys its severity.

The distinction between these two levels matters beyond satisfying curiosity about anatomy. It matters because the correlation between your reported symptoms and the specific nerve root that your imaging shows to be compressed is one of the primary ways that physicians determine whether the structural finding on your MRI is actually causing your symptoms, rather than simply existing alongside them. Many adults over the age of thirty-five have disc bulges or even mild herniations visible on MRI that cause no symptoms whatsoever. The insurance company evaluating your claim will argue, sometimes aggressively, that your herniation is a pre-existing degenerative condition unrelated to the accident. The counter to that argument is not just your MRI. It is the coherence between your imaging and your clinical presentation, meaning the fact that your symptoms fit the exact nerve root that your imaging shows to be compressed, combined with the timing, meaning the fact that you had none of these symptoms before the accident and all of them after it.

The language your radiologist used in your MRI report is worth understanding carefully because it carries weight in ways that will affect your medical treatment and your legal claim simultaneously. A disc herniation and a disc bulge are not the same thing. A bulge is a generalized extension of the disc beyond its normal boundary without a focal tear in the outer ring. A herniation involves a tear in the annulus and the displacement of nuclear material through that tear. A herniation that has broken through the outer ring entirely and separated from the parent disc is called a sequestered or free fragment herniation, and it is the most severe and often the most painful type because the free fragment can move and can irritate the nerve root in ways that a contained herniation cannot. The terms protrusion, extrusion, and sequestration describe progressively more severe disruptions of disc architecture, and each term appearing in your report carries a distinct clinical and legal significance. If your report uses any of these terms, it is worth asking your treating physician specifically what each means in the context of your particular injury and what it implies about your prognosis.

There is also language that may appear in your report describing the disc space height, the degree of foraminal narrowing, and the presence or absence of Modic changes in the adjacent vertebral endplates. Modic changes are signal alterations in the bone directly adjacent to the disc that appear on MRI and are divided into types based on what they indicate about the biological activity in that area. Type 1 Modic changes indicate acute inflammatory activity and are associated with a more recent or active injury process. Type 2 indicate fatty replacement and tend to appear in more chronic conditions. If your report mentions Type 1 Modic changes at the level of your herniation, that finding is one of the clearest imaging indicators available that the pathology at that level is active and recent rather than long-standing and incidental. Most people never know to ask about this. Most attorneys who do not specialize in serious personal injury cases do not know to look for it either. A radiologist who reviews your imaging specifically in the context of correlating it to a recent trauma can often provide an opinion about the acuity of the findings that a standard diagnostic read does not include.

Electrodiagnostic testing, specifically electromyography and nerve conduction studies, often called EMG and NCS, is the other piece of objective evidence that is underutilized in car accident cervical disc cases. An MRI shows structure. An EMG measures function. It can determine whether a nerve root that appears compressed on imaging is actually conducting electrical signals abnormally, and it can locate the level of dysfunction with considerable precision. A positive EMG finding, one that shows denervation activity or slowed conduction consistent with the level of your herniation, transforms your injury from a structural observation on imaging into a measured, functional impairment of an identifiable nerve. From a medical standpoint, it helps direct treatment. From a legal standpoint, it significantly strengthens the argument that your herniation is producing real neurological impairment rather than just appearing on a film. If your treating physician has not yet ordered electrodiagnostic testing and you have ongoing arm pain, numbness, or weakness, it is worth asking directly whether this testing is appropriate for your presentation.

On the question of pre-existing degeneration, here is what the insurance company will not tell you and what your attorney absolutely must know. The legal standard in Missouri and in most states does not require your spine to have been perfect before the accident in order for you to recover full compensation for what the accident did to you. The eggshell plaintiff doctrine, sometimes called the thin skull rule, holds that a defendant takes the plaintiff as they find them. If your discs were already showing some degree of age-related wear and the force of the crash herniated a disc that might not have herniated in a twenty-year-old spine, the defendant is still responsible for the full consequences of that herniation. What matters is whether the accident caused or significantly aggravated a symptomatic condition. If you were not experiencing neck pain, arm numbness, or shoulder weakness before the crash and you are now, the acceleration of a pre-existing vulnerability by the trauma of the collision is a compensable injury. The insurance adjuster who tells you that your MRI shows degenerative changes and therefore the herniation is not related to the crash is not giving you legal analysis. They are giving you a negotiating position.

Surgical decisions in cervical disc cases are among the most consequential that a car accident victim faces, and they sometimes feel rushed by pain that has become intolerable. The two most common surgical interventions for C4-C5 or C5-C6 herniations are anterior cervical discectomy and fusion, known as ACDF, in which the disc is removed and the adjacent vertebrae are fused together, and cervical disc replacement, in which the damaged disc is replaced with an artificial one that preserves some range of motion. The choice between them has implications for your long-term spine health and for the adjacent segment disease that can develop over time in a fused spine. Most spine surgeons will attempt conservative treatment, including physical therapy, epidural steroid injections, and activity modification, before recommending surgery, but there are situations involving progressive neurological weakness or signs of cord compression that warrant more urgent surgical consideration. If you are experiencing hand weakness that is getting worse, difficulty with fine motor tasks like buttoning a shirt, or any symptoms that suggest your spinal cord rather than just a nerve root may be involved, those symptoms warrant an urgent call to your physician regardless of where you are in the legal or insurance process.

The practical reality of where you are right now is this. You have a serious injury to a part of your body that you will have for the rest of your life. How it is documented in the coming weeks, how consistently you attend treatment, how thoroughly your medical providers record the connection between the accident and your symptoms, and whether the right imaging and functional testing is ordered in a timely way will all directly affect both your recovery and the strength of your claim. The insurance company for the at-fault driver is already building a file on your case. What they put in that file and what your medical record says need to tell the same coherent story, and the time to start building that story accurately is right now, not when the case settles and not when the statute of limitations is about to run.

This article is intended for general informational purposes only and does not constitute legal or medical advice. Cervical disc injuries vary significantly in severity, presentation, and appropriate treatment, and only a qualified medical provider can evaluate and treat your specific condition. If you were injured in a car accident and have been diagnosed with or suspect a herniated disc, you should consult both a treating physician and a licensed personal injury attorney in your state as soon as possible. Missouri’s statute of limitations for personal injury claims is five years from the date of the accident, but gathering evidence and beginning treatment promptly is essential regardless of the deadline.