The Grostic Dentate Ligament–Cord Distortion Hypothesis: How Your Upper Cervical Spine May Influence the Nervous System

By Dr. Devin Carr, DC | Soda City Chiropractic | Columbia, SC

When people think about chiropractic care, they often imagine a treatment for back pain, neck stiffness, or headaches. But my approach to chiropractic goes deeper. I am interested in how spinal biomechanics influence the nervous system, how the body processes sensory information, and how those relationships affect movement, posture, and pain.

One hypothesis that has influenced my understanding of upper cervical chiropractic is the Dentate Ligament–Cord Distortion Hypothesis, proposed by Dr. John D. Grostic in 1988.

Although this theory has not been fully validated through clinical research, it offers a fascinating mechanical explanation for how the relationship between the upper cervical vertebrae and spinal cord might influence neurological function.

What Is the Dentate Ligament–Cord Distortion Hypothesis?

The spinal cord is not simply floating freely inside the vertebral canal. It is surrounded by protective membranes and supported by connective tissues, including structures called dentate ligaments, also known as denticulate ligaments.

These ligaments extend laterally from the spinal cord toward the surrounding dura mater. Their role includes helping stabilize the cord while allowing normal movement.

Grostic proposed that abnormal positioning or movement of the upper cervical vertebrae, particularly the atlas (C1) and axis (C2), could transmit mechanical tension through these attachments.

Imagine a rope being pulled more strongly from one side than the other. Uneven tension changes how forces are distributed through the structure.

In theory, abnormal lateral tension on one side of the spinal cord could produce a similar mechanical distortion.

Over time, chronic mechanical loading can cause connective tissues to adapt and remodel. One possibility worth investigating is whether prolonged abnormal tension could contribute to thickening or changes in the dentate ligaments themselves.

However, research has not demonstrated that routine upper cervical misalignments cause pathological dentate ligament thickening or spinal cord distortion. This remains an important unanswered question.

Anatomical investigations by Tubbs and colleagues have confirmed that cervical dentate ligaments can transmit mechanical forces and help stabilize the spinal cord.

Could Mechanical Tension Affect Spinal Cord Circulation?

One of the most interesting aspects of Grostic's theory concerns the possibility of altered spinal cord circulation.

The spinal cord requires a continuous supply of oxygenated blood. The anterior spinal artery provides circulation to approximately the anterior two-thirds of the spinal cord, including important motor and sensory pathways.

Grostic proposed that abnormal mechanical tension might affect local circulation through vascular distortion or impaired venous drainage.

The proposed concern is that restrictions in venous outflow could create congestion and changes in local pressure, somewhat analogous to backpressure when veins cannot drain efficiently.

This is different from claiming that blood actually reverses direction through the anterior spinal artery.

The relationship between blood flow, tissue pressure, and spinal cord function is well established in neurological medicine. What remains unproven is whether ordinary C1–C2 biomechanical dysfunction creates these vascular disturbances or whether chiropractic adjustments reverse them.

The Ischemic Penumbra: Could Nerve Tissue Become Less Active?

Another concept that interests me is the ischemic penumbra.

In neurological research, the ischemic penumbra describes tissue experiencing inadequate blood supply that may remain alive despite impaired function. Under certain conditions, restoring circulation can allow recovery of neurological activity.

When oxygen availability decreases, cells may struggle to maintain normal energy production, and severe oxygen deprivation can shift cellular metabolism toward less efficient anaerobic pathways.

This raises an interesting theoretical question: Could prolonged mechanical stress or circulation changes create areas of reduced neurological activity without immediate permanent damage?

It is an intriguing hypothesis, but an important distinction must be made. The ischemic penumbra is primarily established in research involving acute ischemic injuries, particularly stroke. There is currently no convincing evidence that common upper cervical misalignments create an ischemic penumbra within the spinal cord.

I view this concept as an area deserving further investigation, not an established explanation for chiropractic outcomes.

Two Important Neurological Pathways: Proprioception and Pain

Why would mechanical or circulatory disturbances matter?

The spinal cord contains pathways responsible for communicating information between the body and brain. Two particularly relevant pathways are the spinocerebellar and spinothalamic tracts.

Spinocerebellar Tracts: Proprioception, Balance, and Posture

The spinocerebellar tracts carry unconscious proprioceptive information to the cerebellum.

Proprioception allows your nervous system to monitor the position and movement of your body without requiring conscious attention.

These pathways contribute to coordination, postural control, and how muscles work together during movement. Other pathways, including the posterior columns, also participate in proprioception.

Consider someone experiencing chronic neck stiffness, poor movement coordination, or difficulty controlling their shoulder blade.

Altered sensory information from joints and muscles may contribute to dysfunctional movement patterns, even without injury to the spinal cord itself.

This is one reason I evaluate posture, balance, joint motion, and muscular coordination—not simply pain intensity.

Spinothalamic Tracts: Pain, Temperature, and Nociception

The spinothalamic pathways transmit information related to pain, temperature, and aspects of touch.

Nociception is the nervous system's process of detecting potentially harmful stimuli. However, nociception and the conscious experience of pain are not identical.

Pain is influenced by sensory input, previous experiences, central processing, and the nervous system's sensitivity.

When pain-processing pathways become persistently amplified, some individuals develop features of central sensitization.

Possible symptoms include:

• Pain that feels disproportionate to an ordinary movement or stimulus.

• Increased tenderness or sensitivity to pressure.

• Pain from light touch that would not ordinarily hurt.

• Pain spreading beyond the original painful region.

• Persistent discomfort after an injury has healed.

• Greater sensitivity to certain sensory stimuli.

Central sensitization is a recognized mechanism in chronic pain, but it has not been established that dentate ligament tension or Grostic's proposed vascular changes directly cause it.

How Might Upper Cervical Chiropractic Adjustments Help?

This brings us to the question that shapes much of my chiropractic philosophy: Can improving spinal mechanics influence how the nervous system functions?

Research from Dr. Heidi Haavik and colleagues has shown that spinal manipulation can produce measurable short-term changes in somatosensory processing and certain measures of sensorimotor integration.

For example, a 2024 randomized study involving 96 adults reported a change in a cortical sensory-response measurement after an upper cervical thrust directed at a clinically selected spinal segment.

That does not prove an adjustment reduces dentate ligament tension, restores spinal cord blood flow, or reverses an ischemic penumbra.

It does, however, support investigating chiropractic adjustments as interventions that influence neurological processing, rather than viewing them exclusively as treatments for local joint stiffness.

At Soda City Chiropractic, I use individualized chiropractic adjustments to address mechanical restrictions and musculoskeletal symptoms. I also incorporate soft-tissue therapy, proprioceptive training, corrective exercise, and movement rehabilitation when appropriate.

For patients seeking a neck pain chiropractor in Columbia, SC or a shoulder pain chiropractor in Columbia, SC, my goal is to evaluate how the spine, joints, muscles, and nervous system work together.

When clinically appropriate, I may use upper cervical techniques, including our Y-axis chiropractic adjustment, a controlled manual occipital-lift technique.

No particular adjustment has been proven to release a medullary lock or correct spinal cord ischemia. Suspected spinal cord dysfunction or compromised circulation requires medical evaluation rather than manipulation.

My Chiropractic Philosophy: Better Movement, Better Function

I believe chiropractic should be about more than temporarily reducing pain.

The spine is part of a complex system that integrates mechanical movement, sensory input, muscle control, and neurological processing.

The Grostic hypothesis encourages us to ask important questions about how these systems interact.

As a chiropractor in Columbia, SC, I want my patients to understand that improving their health involves more than one intervention. Chiropractic care, strengthening, mobility exercises, proper sleep, nutrition, and stress management all deserve consideration.

The goal is to help patients move better, improve function, manage discomfort, and develop the physical capacity to participate confidently in daily life.

Frequently Asked Questions

1. Can an upper cervical adjustment improve nervous system function?

Research suggests spinal manipulation can temporarily influence certain neurological measurements, including sensory processing and motor control. However, there is insufficient evidence that upper cervical adjustments directly relieve spinal cord distortion, improve spinal cord circulation, or produce broad systemic neurological benefits.

2. Can problems in my neck contribute to shoulder pain or poor posture?

Yes. Cervical joints, nerves, muscles, and shoulder mechanics are closely related. Some neck conditions can refer pain toward the shoulder, while altered neck and shoulder muscle function can influence movement and posture. Not all shoulder pain originates in the neck, so an examination is important.

3. What is the difference between an upper cervical adjustment and a Y-axis adjustment?

Upper cervical chiropractic is a broader approach focused on evaluating and treating the upper neck, particularly C1 and C2. A Y-axis adjustment is a specific manual technique using a controlled force along the length of the cervical spine. At Soda City Chiropractic, I select techniques according to each patient's examination, symptoms, and clinical needs.

Explore Upper Cervical Chiropractic in Columbia, SC

If you are looking for an upper cervical chiropractor in Columbia, SC or researching a Y-axis chiropractor in Columbia, SC, I invite you to learn more about our approach to spinal health and neurological function.

At Soda City Chiropractic, we combine chiropractic adjustments with individualized movement and rehabilitation strategies to help patients address neck pain, shoulder discomfort, restricted mobility, and related musculoskeletal concerns.

Soda City Chiropractic is located at 2205 Main Street, Columbia, SC 29201. Call 803-966-7689 or visit sodacitychiro.com to schedule your appointment.

Scientific References

1. Grostic JD. (1988). Dentate Ligament–Cord Distortion Hypothesis. Chiropractic Research Journal, 1(1), 47–55.

2. Tubbs RS, et al. (2001). The Denticulate Ligament: Anatomy and Functional Significance. Journal of Neurosurgery.

3. Levine DN. (1997). Pathogenesis of Cervical Spondylotic Myelopathy. Journal of Neurology, Neurosurgery & Psychiatry.

4. Heiss WD. (2012). The Ischemic Penumbra: How Does Tissue Injury Evolve?. Annals of the New York Academy of Sciences.

5. Haavik-Taylor H, Murphy B. (2007). Cervical Spine Manipulation Alters Sensorimotor Integration. Clinical Neurophysiology.

6. Niazi and colleagues. (2024). A Randomized Controlled Trial Comparing Different Sites of High-Velocity Low-Amplitude Thrust on Sensorimotor Integration Parameters. Scientific Reports.

7. Central Sensitization, Chronic Pain, and Other Symptoms: Better Understanding, Better Management. (2023). Cleveland Clinic Journal of Medicine.