Anterolisthesis of C4 on C5 is a forward slip of the fourth cervical vertebra over the fifth, and it is one of the most frequently affected levels in the neck for this type of displacement. The slip usually results from age-related wear on the discs and small joints that hold the vertebrae in alignment. In many people it causes no symptoms at all and never progresses, but when it does produce trouble, the consequences range from neck pain and stiffness to nerve compression and, in more serious cases, spinal cord dysfunction. Understanding what drives the slip, how it is found, and when it actually matters can spare you unnecessary worry or, conversely, prompt timely treatment.
Why C4-C5 Is a Hot Spot
The cervical spine is built for mobility, and the mid-neck segments bear much of the load during flexion and extension. C4-C5 sits right in the zone of greatest motion, which also makes it one of the zones of greatest wear. A systematic review of degenerative cervical spondylolisthesis found that C4-C5 was involved in about half of all cases, with C3-C4 close behind at roughly 46%.1PubMed Central. Degenerative cervical spondylolisthesis: a systematic review A separate study looking at symptomatic adults reported that C4-C5 was the single most common level for degenerative spondylolisthesis, affected in about 6% of all segments examined.2Spine. Prevalence and Motion Characteristics of Degenerative Cervical Spondylolisthesis in the Symptomatic Adult
Two structural changes converge at this level to encourage forward slipping. First, the intervertebral disc between C4 and C5 loses height as it degenerates, which tilts the vertebra forward. Second, the small facet joints at the back of the spine change shape: as the joint surfaces flatten, they lose their ability to resist forward translation. Research has shown that a decrease in the angle of the lower facet surfaces, combined with loss of disc height at the front of the spine, is the primary driver of anterolisthesis at any cervical level, and C4-C5 is particularly susceptible because of how much motion it handles.3PubMed. Influence of facet joint angles and asymmetric disk collapse on degenerative olisthesis of the cervical spine
How Common Is It
Population studies paint anterolisthesis as surprisingly common, even among people who feel fine. A large general-population study found anterior spondylolisthesis in about 6% of both men and women.4Scientific Reports. Prevalence of cervical anterior and posterior spondylolisthesis and its association with degenerative cervical myelopathy in a general population That means if you lined up a hundred people off the street and took X-rays of their necks, roughly six would show some degree of forward vertebral slip. Posterior spondylolisthesis, where a vertebra slides backward, is actually more common, particularly in men, but anterolisthesis draws more clinical attention because of the way it narrows the spinal canal during certain neck positions.
The prevalence climbs with age. Disc degeneration and facet wear are cumulative processes, so the older you are, the more likely you are to develop some degree of slip. Most of these slips are small, classified as grade 1 (meaning the vertebra has shifted forward by less than 25% of the width of the one below it), and many never come to clinical attention.
When It Causes Symptoms and When It Does Not
The majority of people with mild anterolisthesis at C4-C5 have no idea they have it. The slip is discovered incidentally on imaging ordered for something else, like a whiplash evaluation or a routine workup for headaches. This is worth emphasizing because the term “anterolisthesis” on an MRI report can sound alarming, and many patients assume it means surgery is imminent. In most cases, it does not.
When symptoms do develop, they tend to fall into two categories. The first is mechanical neck pain and stiffness. The unstable segment may ache during prolonged postures, and you might notice grinding or catching sensations with movement. The second, more concerning category involves nerve or spinal cord compression. A forward-slipping vertebra can narrow the openings where nerve roots exit (the neural foramina), producing pain, tingling, or weakness that radiates into the shoulder or arm. If the spinal canal itself becomes tight enough, the cord can be compressed, a condition called cervical myelopathy. Myelopathy symptoms include difficulty with fine hand movements (trouble buttoning a shirt, for instance), an unsteady gait, and sometimes a sense that the legs feel heavy or clumsy.
An interesting wrinkle is that spinal cord compression in patients with degenerative spondylolisthesis sometimes occurs in a position you would not expect. A study of patients with cervical myelopathy caused by spondylolisthesis at C4-C5 found that the cord was compressed not in flexion, where the vertebra slips the farthest forward, but in extension, where bulging disc material and thickened ligaments behind the cord pinch it from behind.5PubMed Central. Cervical myelopathy due to degenerative spondylolisthesis This matters practically: if your symptoms get worse when you look up or tilt your head back, that pattern is consistent with extension-related cord compression rather than the instability itself.
Diagnosing the Slip
The basic starting point is a lateral (side-view) X-ray of the cervical spine. On a neutral standing film, a radiologist can measure how far C4 has slipped forward relative to C5. But a single neutral X-ray misses a meaningful fraction of cases. One study found that about 22% of spondylolisthesis levels were invisible on neutral films alone; those slips only appeared when the neck was flexed or extended.6PubMed Central. The Utility of Flexion-Extension Radiographs in Degenerative Cervical Spondylolisthesis That same study also showed MRI missed nearly 38% of spondylolisthesis levels, because standard MRI is performed with the patient lying down in a neutral position, which can reduce or eliminate a positional slip.6PubMed Central. The Utility of Flexion-Extension Radiographs in Degenerative Cervical Spondylolisthesis
This is why doctors often order flexion-extension X-rays when spondylolisthesis is suspected. You stand in front of the X-ray machine and gently bend your neck forward and then backward while images are taken in each position. The difference in vertebral alignment between the two views reveals dynamic instability, the kind of slip that comes and goes with motion.
MRI remains essential for a different reason: it shows the soft tissues that X-rays cannot, including the spinal cord, nerve roots, and discs. If your doctor is worried about cord compression, MRI is the tool that answers that question. Newer dynamic MRI techniques can capture the spine in flexion and extension positions and simultaneously show whether the cord is being pinched, combining the advantages of both traditional imaging methods.7European Journal of Radiology. Clinical feasibility of 2D dynamic sagittal HASTE flexion-extension imaging of the cervical spine for the assessment of spondylolisthesis and cervical cord impingement These dynamic MRI sequences are not yet standard at every imaging center, but they are becoming more widely available and can be particularly helpful in complex cases where the diagnosis is unclear.
The Natural History: Does It Get Worse Over Time
This is the question most patients ask once they see the word “anterolisthesis” on their report. The reassuring answer, based on the available follow-up data, is that most degenerative cervical slips stay put. A study tracking patients over two to seven years found that none of the anterolistheses in their cohort had progressed at final follow-up, and none of the patients had experienced clinical worsening.8PubMed. The natural history of degenerative spondylolisthesis of the cervical spine with 2- to 7-year follow-up
A larger study with a broader range of patients found that progression of translation occurred in about 9% of cases, and this progression was more common in older patients and in those with anterior (as opposed to posterior) slips. Even so, the progression did not correlate with worsening symptoms.9Spine. Natural History of Cervical Degenerative Spondylolisthesis In other words, the slip might creep forward a bit on X-ray without the patient feeling any different. The degree of slip on imaging and the degree of bother in daily life are not as tightly linked as you might assume.
That said, a small subset of patients does progress to clinically significant spinal cord compression over time, particularly those who start with a narrow spinal canal or who develop additional disc herniations at the same level. If your doctor is monitoring your anterolisthesis conservatively, periodic check-ups and attention to any new neurological symptoms (changes in hand coordination, balance difficulties, or new radiating arm pain) are the practical takeaways.
Treatment When the Slip Is Mild
For grade 1 anterolisthesis without significant nerve or cord compression, conservative management is the first line. This typically includes physical therapy focused on strengthening the deep neck flexors and postural muscles, anti-inflammatory medications for flare-ups, and activity modification to avoid sustained awkward neck postures. Some patients find relief with cervical traction or manual therapy, though the evidence for these is less robust than for exercise-based rehabilitation.
A case report of a patient with traumatic anterolisthesis at C4-C5 illustrates how frustrating the conservative path can sometimes be: the patient relied on pain medications and physical therapy but found the results “poor and unsatisfactory,” with ongoing reliance on analgesics and hot packs.10Journal of Taibah University Medical Sciences. Post traumatic cervical anterolithesis: comprehensive evaluation and expert opinion This case involved a traumatic cause with a facet subluxation and vertebral fracture, which is a different animal from the gradual degenerative slip most patients have. Still, it highlights that not everyone responds well to non-surgical treatment, particularly when the underlying structural damage is severe.
For purely degenerative slips, the picture is brighter. Many patients manage well with periodic physical therapy and lifestyle adjustments, never requiring surgery. Ergonomic changes at work, keeping the monitor at eye level to avoid prolonged flexion, sleeping with a supportive pillow, and maintaining general fitness all contribute to symptom control.
When Surgery Enters the Conversation
Surgery is considered when there is evidence of spinal cord compression causing myelopathy, progressive neurological deficits, or severe radiculopathy that has not responded to conservative care over several months. The goal of surgery is to decompress the neural structures and stabilize the unstable segment so the slip cannot worsen.
There are two broad surgical approaches. An anterior approach goes in through the front of the neck and typically involves removing the damaged disc and fusing C4 to C5 with a bone graft or cage and a small plate. This is the most common procedure for single-level problems. A posterior approach goes in from the back and may involve laminectomy (removing part of the bone roof of the spinal canal) with or without fusion, or laminoplasty (reshaping the canal to give the cord more room). Multi-level disease or certain anatomical configurations favor the posterior route.
A study comparing anterior and posterior approaches for degenerative cervical myelopathy found that patient-reported outcomes at one year, including disability scores, quality of life, pain, and satisfaction, did not differ significantly between the two groups. The anterior group did have shorter hospital stays.11Oxford Academic Neurosurgery. Comparison of Outcomes Following Anterior vs Posterior Fusion Surgery for Patients With Degenerative Cervical Myelopathy: An Analysis From Quality Outcomes Database The choice between approaches depends less on which is “better” overall and more on the specifics of where and how the cord is being compressed, the number of levels involved, and the patient’s overall spinal alignment.
Dynamic Instability and Why Neck Position Matters
One of the trickier aspects of anterolisthesis at C4-C5 is that the slip is often dynamic, meaning it appears or worsens in certain neck positions and reduces or disappears in others. This is why a patient can have a completely normal-looking MRI taken while lying flat, yet experience symptoms when upright and moving. The translational motion at levels with grade 1 spondylolisthesis has been measured as greater than at unaffected segments, even though the angular (tilting) motion is not necessarily different.2Spine. Prevalence and Motion Characteristics of Degenerative Cervical Spondylolisthesis in the Symptomatic Adult
This has direct implications for your daily life. If your anterolisthesis is dynamic, sustained flexion (looking down at a phone or laptop for hours) may increase the forward shift and tighten the space around the nerves. Conversely, extension (looking up at a high shelf, painting a ceiling) may compress the cord from behind as the ligaments and disc bulge inward. Neither position is categorically “safe” or “dangerous,” but being aware of which positions provoke your symptoms helps you manage them. A physical therapist familiar with cervical instability can help you identify your specific provocative postures and develop strategies to minimize time in them.
Pseudosubluxation in Children
If you are a parent whose child has had a neck X-ray, you may have encountered the term “anterolisthesis” or “subluxation” at C2-C3 or C3-C4 on the report. In children under about eight years old, the upper cervical vertebrae normally slide forward relative to each other because of the ligamentous laxity and incomplete bony development in young spines. This is called pseudosubluxation, and it is a normal variant, not a sign of injury or degenerative disease. It can look alarming on X-ray, particularly to an emergency physician who is not used to reading pediatric cervical films. The key distinguishing feature is that the posterior spinous-process line (Swischuk’s line) remains intact in pseudosubluxation, whereas it is disrupted in a true injury. If your child’s report mentions forward slip at upper cervical levels after a minor injury and the treating doctor is not concerned, pseudosubluxation is the likely explanation.
Adjacent Segment Effects After Fusion
Patients who undergo fusion surgery at C4-C5, whether for anterolisthesis or for other reasons like disc herniation, sometimes develop problems at the levels above or below the fusion. This phenomenon, called adjacent segment disease, occurs because fusing one level transfers extra mechanical stress to the neighboring segments. Those segments may then accelerate their own degeneration, potentially developing disc herniations, bone spurs, or spondylolisthesis of their own.
This pattern is particularly well documented in patients with Klippel-Feil syndrome, a congenital condition in which certain cervical vertebrae are fused from birth. A study of these patients found that the two most common levels for spondylolisthesis adjacent to a congenitally fused segment were C3-C4 and C4-C5.12Translational Research in Anatomy. Adjacent segment level disease in Klippel-Feil syndrome patients with congenital cervical fusion in the setting of anterolisthesis: Should management be altered in the presence of anterolisthesis? The takeaway for anyone facing cervical fusion is that the surgery solves one problem but creates a long-term surveillance need at the neighboring levels. This does not mean fusion is a bad idea when it is indicated; it means that follow-up imaging every few years, along with continued attention to neck strengthening and posture, is part of the package.
When the Report Sounds Worse Than It Is
Radiology reports are written for other doctors, not for patients, and they tend to describe everything they see, whether it matters or not. A report that reads “anterolisthesis of C4 on C5 with mild disc desiccation and facet hypertrophy” can send you to Google in a panic, but translated into plain English it often means: the disc is a bit dried out and the joints have some extra bone growth, and C4 has shifted forward a small amount. These findings are extremely common in people over 50 and are often unrelated to whatever symptom prompted the imaging in the first place.
The critical question is not whether anterolisthesis is present but whether it is causing the symptoms you actually have. That determination requires a clinician to match the imaging findings with your specific neurological examination, your symptom pattern, and sometimes additional tests like nerve conduction studies. A slip on imaging plus no matching clinical picture equals an incidental finding. A slip on imaging plus arm weakness in the distribution of the C5 nerve root equals a probable cause that may warrant treatment. The imaging alone does not tell you which category you fall into, which is why interpreting your own MRI report without medical guidance tends to create more anxiety than clarity.