In a proportion of these patients, the explanation is hypermobility.

Who Hypermobile Patients Are

Hypermobility refers to a constitutional tendency toward greater than normal joint and soft tissue laxity. The 2017 international EDS classification describes hypermobile Ehlers-Danlos syndrome and related hypermobility spectrum disorders as heritable connective tissue conditions characterized by joint hypermobility, skin hyperextensibility, and tissue fragility, with persistent pain and joint instability as hallmark clinical features.

In clinical practice, hypermobile patients present with a recognizable set of features. They commonly have a history of natural flexibility from childhood, often having performed dance, ballet, gymnastics, or other activities that rewarded their unusual range of motion. They may have been the child who could do the splits effortlessly, or the gymnast who seemed to move differently from their peers. Their skin often has a softer, more elastic quality than average. Their joints are prone to subluxation and dislocation with relatively minor provocation, and many carry histories of recurring ankle sprains, shoulder instability, or joint injuries that seemed disproportionate to the force involved.

In my practice, hypermobile patients represent approximately 30 percent of the complex chronic pain group. This is a clinical observation from my patient population and does not reflect published population prevalence figures, which vary considerably depending on the diagnostic criteria and population studied. Symptomatic care-seeking cohorts in this category are often female-predominant, and research suggests hormonal factors influence ligament laxity and pain presentation, though the degree of sex difference in baseline constitutional hypermobility varies across studies.

Why Hypermobility Creates a Diagnostic Problem

Standard clinical assessment of spinal injury relies heavily on range of motion. A cervical spine that moves freely and fully through its range is generally assumed to be healthy or minimally injured. Loss of range of motion is treated as a primary indicator of injury severity.

This logic fails in hypermobile patients for a straightforward reason: their baseline range of motion is above normal. A hypermobile individual who has sustained a significant whiplash injury may still demonstrate range of motion that appears normal or even above normal to a clinician who does not know their pre-injury baseline. The injury is present and clinically significant, but the range of motion sign that would flag it in a non-hypermobile patient is absent.

A 2022 cross-sectional study published in PeerJ found that hypermobile individuals with nonspecific neck pain had worse cervical joint-position error and lower neck muscle endurance than hypermobile individuals without neck pain, and that higher hypermobility scores tracked with greater cervical position-sense deficit and lower endurance. This supports the broader clinical premise that hypermobility alters cervical stability, proprioception, and pain presentation in ways that standard examination may not capture.

The problem compounds on imaging. The loose joint structure of hypermobile individuals means spinal segments move through a greater arc during a whiplash event. The resulting soft tissue injuries may not produce the disc or bony changes that standard MRI protocols are designed to detect. A systematic review and meta-analysis in the Journal of Magnetic Resonance Imaging concluded that the clinical significance of many cervical MRI findings in whiplash remains uncertain, and that near-normal MRI cannot be treated as a reliable rule-out for clinically important post-whiplash pathology.

What Emerging Research Shows About Occult Nerve Involvement

An important and growing area of whiplash research supports the idea that some patients classified under standard grading systems as having no apparent neurological injury may still have meaningful nerve involvement that standard bedside testing does not detect.

A 2025 prospective cohort study published in Brain found that a significant proportion of acute WAD II participants had neuropathic pain features, sensory hypoaesthesia, and elevated neurofilament light, a biomarker of axonal injury. The authors explicitly argued that these findings challenge the traditional assumption that WAD II is solely a musculoskeletal condition. A 2024 study found elevated T2 signal in cervical dorsal root ganglia and brachial plexus roots in acute WAD II, consistent with peripheral neuroinflammation.

These findings are relevant to hypermobile patients specifically because their presentation, with preserved or even excessive range of motion and limited standard examination findings, may place them in lower-grade WAD classifications that prompt less thorough neurological investigation, precisely the population in which occult nerve involvement is most likely to be missed.

Spinal Myelopathic Syndrome in Hypermobile Patients

After a significant whiplash event, hypermobile patients are at elevated risk of developing what I describe as Spinal Myelopathic Syndrome, or SMS. This is a clinical framework I use to describe injury and functional compromise at or near the level of the spinal cord, producing a symptom pattern that closely resembles post-concussion syndrome: widespread body aches, arm and leg symptoms, fatigue, cognitive changes, and sensory disturbances, without obvious trigger or significant ROM loss on examination.

SMS as a named syndrome is not currently validated in the indexed literature, and I present it as a clinical observation framework rather than an established diagnosis. What the emerging research does support is the plausibility of cord-root or near-cord involvement in a subgroup of patients who would traditionally be classified as having no neurological injury. The Brain cohort noted that a preganglionic component involving cervical dorsal roots or possibly spinal cord structures could not be excluded in a subset of their WAD II patients.

In hypermobile patients, the mechanics of the injury pattern mean that spinal segments move through a greater arc during trauma, and the stabilizing tissue that forms in response may develop in positions that create different alignment and tension patterns than in a non-hypermobile individual. This is a clinical hypothesis grounded in observation and in the emerging nerve-pathology literature. It warrants dedicated research.

What Assessment Should Include

Every assessment of a patient with chronic pain following whiplash should include a hypermobility evaluation as a standard component. The Beighton score remains the standard screening tool for generalized joint hypermobility, and research supports its clinical utility when hypermobility is suspected. This is not currently routine in most clinical settings, and that gap contributes directly to the underdiagnosis of this patient group.

When hypermobility is identified, range of motion findings must be interpreted against the patient’s expected hypermobile baseline rather than against population norms. A cervical spine that demonstrates full range of motion in a hypermobile patient after whiplash is not a reassuring finding. It is potentially a marker of a more serious underlying injury pattern that standard assessment tools are not designed to detect.

If a hypermobile patient shows significant loss of range of motion following whiplash, that finding should be treated as a particularly serious clinical signal, precisely because their expected baseline mobility is higher than average. Restricted range of motion in a constitutionally hypermobile patient indicates a degree of structural compromise that would generate far greater restriction in a non-hypermobile individual.

The assessment in these patients should also include attention to sensorimotor features, upper cervical stability, autonomic symptoms, and neuropathic pain characteristics, particularly when symptoms are disproportionate to standard examination findings. The emerging WAD literature suggests these features may be present in patients whose classification would not traditionally prompt that level of investigation.

Hypermobility does not protect against whiplash injury. In clinical observation, it increases the risk of serious spinal injury being missed.

The information in this article is educational and informational in nature. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing chronic pain following a whiplash injury and have a history of joint hypermobility, consult with a qualified healthcare provider to discuss appropriate assessment and care.