Effect of Postural and Cervical Muscles on the Occlusion

Why the Cervical Muscles Cannot Be Separated From the Bite

Originally published January 2016 · Last updated May 2026

Abstracted from Chapter IIA of Neuromuscular Dental Diagnosis and Treatment, by Dr. Robert Jankelson, DDS — Ishiyaku EuroAmerica, St. Louis, Missouri, 2005 2nd Edition

Why the Masticatory Muscles Cannot Be Considered in Isolation

The influence of muscle forces and vectors on mandibular position cannot be limited to the masticatory muscles alone. Cervical and postural muscles also play a role.

An ideal erect posture is a line of gravity down the midline of the following bilateral points:

The center of the mastoid process
The point just anterior to the shoulder joints
The point through the hip joints
The point just anterior to the center of the knee joints
The point in front of the ankle joints

The head will attempt to maintain a posture with its center of gravity midway between the mastoid processes. The maintenance of this center of gravity is essential for the optimal neuromuscular function of the masticatory muscles.

The Cervical and Postural Muscles That Influence the Mandible

The following muscle groups play a major role in maintaining head posture and coordinating mandibular function:

Suprahyoid
Infrahyoid
Posterior cervical
Anterolateral cervical
Anterior cervical
Other cervical / upper thoracic muscles

Together, a finely coordinated, dynamic balance of cervical and cranial muscles determines mandibular movement.

What the EMG Reveals After Myomonitor Application

Patients with cranio-cervical and postural issues often exhibit high EMG readings in some of the muscles even after 45 minutes of Myomonitor application. In some cases the EMG readings may actually increase.

This may be the result of nociceptive input emanating from cervical and postural muscles that passes through the caudate nucleus of the trigeminal ganglion and affects the masticatory muscles.

The Clinical Consequence of Ignoring Cervical Tension

Failure to recognize the postural issues and muscle tension in the cervical-upper thoracic area can have a negative impact on arriving at an optimal and stable occlusion — and can result in relapse of the treated TMJ / MSD patient.

If nociceptive areas are not relieved of pain and spasm, they refer pain to other sites. A myofascial trigger point (TP) is a hyperirritable locus within a taut band of skeletal muscle tissue and the associated fascia. Active trigger points may refer pain to masticatory muscles.

Clinical Solution — Cervical and Trapezius J5 Dental TENS Application

Patient seated with J5 Dental TENS electrodes placed for cervical and masticatory muscle relaxation during occlusal evaluation — demonstrating the cervical-trapezius placement protocol — Dr. Clayton Chan, Occlusion Connections, Las Vegas By placing the electrodes over the upper trapezius muscle (a common trigger point site), the stimulator can relax the upper shoulder and cervical muscles, leading to a more effective occlusal evaluation and subsequent bite registration.

The J5 Dental TENS — a four-channel ULF TENS unit — allows the clinician to effectively relax the masticatory and cervical/postural muscles through the simultaneous stimulation of all the muscles that maintain mandibular rest and head posture, and thus aids clinicians to successfully perform a bite registration procedure. The J5 stimulates these muscles through neural mediation and by direct stimulation. The patient is pulsed for about 45 minutes with the J5. Just prior to starting the bite registration procedure, the clinician turns off stimulation to the cervical/thoracic muscles and follows standard optimizing bite registration procedure as with the J4.

Unpacking the Trigeminal-Cervical Convergence Mechanism

The reference to the caudate nucleus of the trigeminal ganglion in the abstract above deserves a deeper unpacking, because this anatomical structure is the neurophysiologic key to everything that follows.

Anatomical illustration of the trigeminal-cervical convergence pathway showing the trigeminal ganglion, the caudate nucleus extending caudally from the pons into the upper cervical spinal cord, and the convergence of sensory neurons with C1, C2 and C3 cervical nerves — the neuroanatomical basis of the cervical-occlusal relationship — Dr. Clayton Chan, Occlusion Connections, Las Vegas The trigeminal nucleus caudalis — the modern anatomical name for what Dr. Jankelson called the caudate nucleus of the trigeminal ganglion — is not confined to the brainstem. It extends downward into the upper cervical spinal cord, where it shares sensory neurons with the cervical nerves C1, C2 and C3. This anatomical convergence is the reason cervical and masticatory systems cannot be treated as separate territories.

What this means clinically:

A trigger point in the upper trapezius can fire a pain signal that the brain interprets as masseter or temporal pain
A patient’s “TMJ headache” may originate in the suboccipital muscles or the upper cervical spine — not in the temporomandibular joint itself
An occlusal interference at the second molar can produce cervical muscle tension through this same convergence pathway in the opposite direction
The cervical-occlusal relationship is not theoretical — it is hard-wired anatomy

This is why K7 EMG measurement of both the masticatory muscles AND the cervical group muscles is fundamental to GNM diagnosis. The cervical EMG channels are not optional add-ons — they are essential to seeing what the trigeminal-cervical convergence is actually doing in any given patient.

Clinical Signs of Cervical-Occlusal Involvement

Dr. Jankelson’s chapter establishes the neurophysiologic principle. Here is how that principle reveals itself in real clinical patients — the signs every GNM clinician should learn to recognize:

EMG readings fail to normalize after 45 minutes of J5 Dental TENS — particularly in the cervical group channels. The muscles are not relaxing because the underlying cervical-postural input is still driving them
Patient reports neck pain AND jaw pain together — and is often unsure which started first
Forward head posture documented on lateral cephalograms — with associated cervical lordosis loss or kyphotic compensation
Trapezius and upper shoulder tension that never fully releases — even after chiropractic, massage, or physical therapy
Pain referred from upper trapezius to temple, masseter, or jaw — the trigeminal-cervical convergence in clinical action
Symptoms recur after dental treatment alone — when the cervical component was never assessed
The patient feels worse after a dentist who “only adjusted the bite” — because removing occlusal interferences without managing cervical-postural input can paradoxically increase cervical compensation
Occipital headaches, suboccipital tenderness, retro-orbital pain — all consistent with referred pain through the trigeminal-cervical convergence pathway

When these signs are present, treating the bite without addressing the cervical-postural component will not produce lasting resolution.

The 20-Year Intellectual Story — From 2005 Observation to 2026 Neurophysiologic Explanation

What Dr. Jankelson recognized clinically in 2005 — that cervical EMG readings can paradoxically increase even after 45 minutes of TENS, that nociceptive input from cervical muscles passes through the trigeminal caudate nucleus, that anterior-only TENS application fails to resolve cervical muscle tension — has been validated, expanded and explained neurophysiologically over the two decades since.

Two decades later, Dr. Clayton A. Chan extended Dr. Jankelson’s foundational observation into the full neurophysiologic explanation that GNM now teaches — documenting the trigeminal-cervical convergence pathway, the proprioceptive vacuum mechanism, and the five-stage neurophysiologic resolution that occurs when posterior occlusal support is properly established.

The modern GNM clinical answer to the question Dr. Jankelson’s chapter raised is documented in detail at:

Why Posterior Occlusal Support Matters — The Neurophysiologic Explanation of Why Anterior Deprogrammers Cannot Relax the Cervical Muscles →

That page documents the trigeminal-cervical convergence pathway, the proprioceptive vacuum mechanism, the gamma motor neuron sensitization, and the five-mechanism neurophysiologic resolution that the GNM anatomical orthotic provides — built directly on the foundation Dr. Jankelson established. Together these two pages tell the complete intellectual story — observation in 2005, neurophysiologic explanation in 2026.

Reference

Clinical Tips and Information on NMD, Volume 44 — January 2016 Myopearls.

Original source: Jankelson R. Neuromuscular Dental Diagnosis and Treatment. 2nd Edition. Ishiyaku EuroAmerica, St. Louis, Missouri; 2005. Chapter IIA.

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Written by Clayton A. Chan, D.D.S. — Founder and Director, Occlusion Connections | Las Vegas, Nevada