Laboratory StudyEtiology & MechanismsClinical RelevanceDOI
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Patient-friendly summary

If you read nothing else

Cadaver study maps nerve entry points in the temple muscle and finds they line up with known jaw pain trigger points.

Bottom line

Worth discussing with your provider if you have jaw or temple pain, because the findings suggest trigger points may follow a nerve map in the temple muscle.

Preliminary evidence

Think of it like

Trigger points are like knots that form where the puppet strings attach to the muscle.

The deep temporal nerve is the puppet string that moves your temple muscle. The study found the string attaches most often in two middle zones of the muscle. Those same zones match the spots doctors call trigger points. If the string pulls too hard or the attachment gets irritated, a painful knot forms right there.

Body regions

temporal muscletemplejawmandibletemporomandibular joint

How it works

  1. 1
    Nerve entry
    Branches of the deep temporal nerve enter the temple muscle mainly in zones 2 and 5, near the middle of the muscle.
  2. 2
    Motor endplate zone
    These entry points sit close to motor endplates — the spots where nerve signals tell muscle fibers to contract.
  3. 3
    Chemical overload
    After overuse or injury, a nerve chemical called acetylcholine can build up and overstimulate the muscle.
  4. 4
    Knot forms
    The overstimulated muscle fibers stay bunched up, creating a tender trigger point.
  5. 5
    Pain spreads
    That irritated spot sends pain signals to the jaw, temple, or nearby areas, which doctors call referred pain.

Published

2024
2 years ago
Current
Full research — for clinicians and curious readers

Study Summary

Background

Myofascial pain syndrome (MPS) affects nearly three-quarters of the world's population and commonly involves the temporal muscle, which is frequently implicated in temporomandibular dysfunction (TMD). While four trigger points have been clinically described in the temporal muscle by Travell and Simons, no anatomical basis for these trigger points has been established. Understanding the relationship between nerve innervation patterns and trigger point locations could provide crucial insights into the pathophysiology of myofascial pain and improve treatment approaches.

What They Did

Researchers dissected temporal muscles from 14 adult cadavers (6 males, 8 females) to map the branching pattern of the deep temporal nerve. They divided each muscle into six anatomical zones using a coordinate system and carefully documented where nerve branches entered the muscle belly. Using pins and photography, they recorded entry points and analyzed the distribution pattern statistically. The team measured muscle dimensions and correlated nerve entry points with previously described clinical trigger point locations.

What They Found

Deep temporal nerve entry points were found in all six muscle zones, but the distribution was not uniform. Areas 2 and 5 (corresponding to the middle regions of the upper and lower muscle) had the highest number of nerve entries, with area 2 being most densely innervated. Areas 1 and 6 (anterior-upper and posterior-lower regions) had significantly fewer nerve entry points (p<0.05). The pattern of nerve branching corresponded closely to the clinically described trigger point locations from Travell and Simons.

Interestingly, the areas with the most nerve entries corresponded to muscle fibers responsible for jaw elevation, while areas with fewer entries related to jaw retraction movements.

What This Means

This study provides the first anatomical evidence supporting the clinical observation of trigger point locations in the temporal muscle. The correlation between nerve entry points and trigger point sites suggests that dysfunction at motor nerve endings may be a key mechanism in myofascial pain development. For clinicians, this research offers a scientific foundation for targeted treatments like dry needling, providing anatomical guidance for needle placement. It also helps explain why certain areas of the temporal muscle are more prone to developing trigger points.

For patients with temporomandibular dysfunction or chronic facial pain, this research validates the clinical approach of treating specific zones in the temporal muscle and may lead to more precise, effective treatments.

55/100
Evidence StrengthModerate
Study Quality
Sample Size
Replication
p<0.001
Statistical Significance
6
Anatomical Zones
14
Cadavers Studied

Results Comparison

Nerve Entry Points by Zone

entry points
Zone 2 (Upper-Middle)3.5 entry points
Zone 5 (Lower-Middle)3 entry points
Zone 1 (Upper-Anterior)1.1 entry points
Zone 6 (Lower-Posterior)0.7 entry points

Key Findings

Deep temporal nerve entry points were found in all muscle zones but with uneven distributionHigh

Areas 2 and 5 showed highest innervation density, corresponding to jaw elevation muscle fibers

Nerve branching pattern correlates with clinically described trigger point locationsHigh

Anatomical mapping matched Travell and Simons trigger point descriptions

Areas responsible for jaw elevation received more nerve branches than retraction areasMedium

Functional muscle regions requiring more strength showed denser innervation

Transverse muscle length correlated with number of nerve entry pointsMedium

Larger muscles showed proportionally more nerve branches (p<0.05)

No correlation between demographic factors and nerve distributionLow

Age, gender, race, and BMI did not affect nerve entry point patterns

Study Methodology
Study Design
Anatomical dissection study using cadaveric specimens
Sample Size
14
Duration
Cross-sectional anatomical study
Population
Adult cadavers (6 males, 8 females, age 56-95 years)
Outcome Measures
Nerve entry point mapping · Muscle measurements · Photographic documentation

Strengths

  • First anatomical study correlating nerve patterns with trigger points
  • Systematic mapping using standardized coordinate system
  • Strong statistical analysis with appropriate power calculation
  • Clear correlation between findings and clinical observations

Limitations

  • Small sample size limits generalizability
  • Cadaveric study may not reflect living tissue dynamics
  • No direct correlation with clinical trigger point sensitivity
  • Limited to temporal muscle only

Key Takeaways for Patients

What This Means for You

  1. 01Painful trigger points in your jaw muscle have a real anatomical basis related to nerve connections
  2. 02Certain areas of the temporal muscle are naturally more prone to developing trigger points
  3. 03Treatments like dry needling can be more precisely targeted based on this anatomical knowledge
  4. 04This research validates that jaw muscle pain patterns are consistent and scientifically explainable
  5. 05Understanding nerve anatomy may lead to better treatment approaches for TMJ and facial pain

Read the Full Paper

Access the complete peer-reviewed study from BioMed Research International

View Full Study

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