Muscle:Temporalis

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The temporalis is a large, fan-shaped muscle of the skull that is one of the primary muscles of mastication. It is among the most clinically important sources of temporal headache and maxillary toothache in the head and neck. Trigger points (TrPs) in this muscle are found in one-third to nearly two-thirds of patients with temporomandibular (TM) disorders. Its referred pain patterns are arranged in distinct "spokes" corresponding to three fibre regions and one central TrP, each referring pain in characteristic directions over the temporal region and downward to specific upper teeth.

The temporalis develops TrPs both as a primary muscle (from bruxism, clenching, trauma, and immobilisation) and as a satellite of key TrPs in the upper trapezius and sternocleidomastoid muscles. Treatment of the temporalis is not complete until TrPs in those two neck muscles have also been inactivated. The temporal artery runs through the muscle and must be identified and avoided during injection.

Anatomy

The temporalis arises from the deep surface of the temporal fascia and from the whole of the temporal fossa superior to the zygomatic arch. The floor of the fossa is formed by the zygomatic, frontal, parietal, sphenoid, and temporal bones.

Inferiorly, it attaches to the medial and lateral surfaces of the coronoid process of the mandible and along the anterior edge of the mandibular ramus, extending almost to the last molar tooth.

The fibres fan out anteroposteriorly from the coronoid process into three functionally distinct groups:

  • Anterior fibres — nearly vertical
  • Middle fibres — oblique; capable of both vertical and retracting force
  • Posterior fibres — nearly horizontal, but bent around the posterior root of the zygomatic arch and thus oriented essentially vertically; function primarily as elevators and retractors

The zygomatic arch covers much of the tendinous attachment to the coronoid process when the mouth is closed. The anterior three TrP regions are attachment TrPs at musculotendinous junctions; TrP₄ is a central TrP in the midfibre region of the posterior belly.

Innervation

The anterior and posterior deep temporal nerves, branching from the anterior division of the mandibular nerve (CN V₃).

Referred Pain Patterns

Temporalis TrPs produce a characteristic set of "spoke" patterns radiating from different regions of the muscle. Each region refers both pain and tenderness — including hypersensitivity of the upper teeth to percussion, heat, and cold — which can lead to unnecessary dental treatment if the muscle is not examined.

TrP locations and referred pain — Temporalis
TrP Type Location Essential referred zone Key clinical note
ATrP₁ Attachment Anterior portion, musculotendinous junction Forward along supraorbital ridge; downward to upper incisor teeth Most anterior "spoke." Tooth hypersensitivity to heat/cold. Can mimic dental pulpitis.
ATrP₂ Attachment Intermediate portion, musculotendinous junction Upward in finger-like projection to mid-temple; downward to intermediate maxillary teeth Middle "spoke." Tooth hypersensitivity.
ATrP₃ Attachment Intermediate portion (more posterior), musculotendinous junction Upward to mid-temple; downward to posterior maxillary teeth; deeply to maxilla and TMJ Deep fibres in this region may refer pain to the maxilla and TM joint (similar to deep masseter).
CTrP₄ Central Midfibre region of posterior belly, above and slightly behind the ear Backward and upward over the posterior temporal region Posterior "spoke." Found above and slightly behind the ear. Activated by retrusive bruxism.

Deep tenderness may be found in each pain reference zone even when the corresponding TrPs are latent (clinically silent). Sometimes toothache with hypersensitivity to ordinary stimuli (biting, heat, cold) is the chief complaint rather than headache — unaware clinicians may needlessly extract perfectly healthy teeth or extirpate pulps.

Activation and Perpetuating Factors

Trauma and Immobilisation

  • Bruxism and clenching — the most common activating factors; retrusive bruxism particularly activates the posterior fibres and CTrP₄
  • Direct trauma — fall on the head, impact from a golf ball or baseball, head impact against a car door in a motor vehicle accident
  • Prolonged jaw immobilisation — extended dental procedures; cervical traction for neck pain without an occlusal splint (the splint-free traction immobilises the mandible in the fully closed position, maximally shortening the temporalis and other elevator muscles — iatrogenic temporalis TrPs may then add facial pain and toothache to the original neck pain complaint)
  • Anteriorly displaced TM disc — the patient experiences a feeling of pressure and repeatedly bites down in an attempt to relieve it, which perpetuates temporalis and masseter TrPs

Postural and Activity Stress

  • Forward-head posture — produces increased activity in the temporalis and can activate and perpetuate TrPs
  • Excessive gum chewing, jaw clenching
  • Excessive tension in suprahyoid and infrahyoid muscles — creates tensile pull on the mandible; the temporalis and masseter contract to counteract this, activating TrPs. This dysfunctional process can be initiated by flexion-extension injuries or perpetuated by excessive forward-head position.
  • Cold draft over the fatigued muscle — cold from a ventilator, air conditioner, or open car window, especially when the patient is fatigued or hypothyroid

Satellite Activation

Temporalis TrPs may develop secondarily as satellites of key TrPs in the upper trapezius and SCM when these lie within the temporal pain reference zones. Inactivating the key upper trapezius TrP has been shown to inactivate a satellite TrP in the temporalis.

TrPs in lower limb muscles have been observed to indirectly reduce maximal interincisal opening through postural chain effects — an example of dysfunction originating in a weight-bearing limb.

Metabolic Perpetuating Factors

  • Low-normal or frankly reduced thyroid hormone levels (T₃ and T₄) increase vulnerability to muscle cooling and perpetuate TrPs — check thyroid function
  • Folic acid deficiency — can cause neuromuscular irritability expressed as bruxism (comparable to "restless legs" from folate deficiency in the lower limbs)
  • Other nutritional deficiencies — see Chapter 4

Chronic Infection and Inflammation

Reflex muscle contraction occurring with any chronic infection or inflammation, when prolonged, can contribute to TrP development. True painful pulpal pathology or an inflamed TM joint, if protracted, may cause temporalis TrPs to develop. These TrPs become self-sustaining and may continue to cause pain after resolution of the original dental or joint pathology. The unaware clinician will continue treating the tooth or joint rather than the TrPs.

Clinical Examination

Two-Knuckle Test

The patient attempts to place a tier of the proximal interphalangeal joints of the first two fingers of the non-dominant hand between the upper and lower incisor teeth. Normal opening is approximately 2½ knuckles (close to 40 mm in adults). Jaw opening is usually reduced only 5–10 mm with temporalis TrP involvement — this modest reduction means ordinary mandibular movement does not cause pain. The patient may report "My teeth don't meet right" rather than pain.

When posterior fibres harbour active TrPs, the mandible is likely to show zigzag deviation during opening and closing — a useful clinical sign.

Posture and Suprahyoid Assessment

Forward-head posture and excessive tension in suprahyoid and infrahyoid muscles should be specifically noted. Screen the TM joints for grating (auscultate or palpate during opening/closing). Grating alone does not contraindicate stretch treatment, but painful joint movement requires expert dental/TMJ examination before proceeding.

Symptoms

  • Head pain felt widely throughout the temple, along the eyebrow, and behind the eye
  • Aching of the upper teeth; hypersensitivity to percussion, heat, or cold in any or all upper teeth on the same side
  • Premature tooth contact ("My teeth don't meet right")
  • Maxillary pain or TMJ pain (from deep ATrP₃ region)
  • Restriction of jaw opening (usually modest — 5–10 mm only)

Trigger Point Examination

The jaws must be partly (not fully) open to place the muscle fibres on the degree of stretch required to optimise palpation. When the jaws are closed and the muscle is slack, palpable bands are more difficult to feel, spot tenderness is reduced, and local twitch responses to snapping palpation may be unobtainable. Ask the patient to allow the jaw to drop into the relaxed open position before palpating.

Central TrPs are found near midfibre in various portions of the muscle. ATrPs are found at musculotendinous junctions above the zygomatic arch and at the tendon attachment to the coronoid process.

The central TrPs are usually located about two finger-breadths above the zygomatic arch in the midfibre portion of their respective taut bands. If an ATrP is found first, palpate back along the taut band cranially to find the corresponding CTrP.

Examination for ATrP enthesopathy is not complete until the insertion region is palpated:

  • Externally — beneath the zygomatic process with the mouth open
  • Internally — on the inner surface of the coronoid process from within the mouth, with pressure directed outward (laterally) against the coronoid process

Across-the-fibre snapping palpation elicits local twitch responses that are often felt more readily than seen in this muscle.

CTrP₄ (posterior spoke) is found above and slightly behind the ear in the midfibre region of the posterior belly.

Differential Diagnosis

Differential diagnosis — Temporalis TrP pain
Condition Key distinguishing features How to differentiate
Upper tooth pulpitis / dental pathology Continuous severe toothache; positive pulp vitality tests; periapical changes on X-ray Temporalis TrP toothache is intermittent, may occur without percussion sensitivity; Two-Knuckle Test shows mild restriction; TrP palpation reproduces the toothache
Tension-type headache Bilateral band-like pressure; featureless Temporalis TrPs produce a unilateral "spoke" pattern with palpable taut bands and referred dental hypersensitivity; treating TrPs resolves the headache
Cervicogenic headache Onset with neck movement; ipsilateral restricted cervical ROM; occipital referral May coexist; temporalis may be a satellite of upper trapezius or SCM TrPs; treat neck muscles first
Temporal arteritis (giant cell arteritis) Age >50; ESR ≥50 mm/hr; tender, non-pulsatile temporal artery; jaw claudication; systemic symptoms Elevated ESR and CRP; temporal artery biopsy; anemia; does not respond to TrP treatment; requires urgent steroid treatment
Polymyalgia rheumatica Bilateral; includes shoulders, neck, back, upper arms, thighs; ESR ≥50 mm/hr; anemia Temporalis TrP pain is unilateral and localised to the temporal region and teeth; ESR and CRP normal
Temporal tendinitis Tendon-attachment tenderness at coronoid process Likely represents ATrP enthesopathy from temporalis TrPs — examine for and treat the central TrPs before steroid injections or surgical procedures
TMJ internal derangement Grating or click on opening/closing; disc displacement on imaging May coexist; TrP-induced sustained muscle tension may increase intra-articular pressure and contribute to disc displacement — treat the TrPs before concluding joint surgery is needed
Diseased tooth (carious) Reproducible toothache on percussion; periapical changes A non-restorable carious tooth can produce referred pain over the temporalis closely emulating TrP referral — confirm dental pathology before attributing to TrPs
SCM / upper trapezius satellite Temporal pain with SCM or trapezius TrPs active Palpate and inactivate SCM and upper trapezius first; temporalis may resolve as a satellite without direct treatment

Temporal Arteritis — Do Not Miss

Temporal arteritis is a medical emergency that can cause blindness. It must always be considered in any patient over 50 with new temporal pain. Distinguishing features: the temporal artery may be tender and non-pulsatile; jaw claudication (pain in the masseter on chewing, relieved by rest) is pathognomonic; ESR is typically ≥50 mm/hr and often ≥100 mm/hr; there is associated anaemia and elevated CRP. Urgent ESR, CRP, and temporal artery biopsy are required. Do not delay steroid treatment while arranging biopsy. This condition does not respond to trigger point treatment.

Treatment

Trigger Point Release

Forward-head posture and tongue position should always be corrected first. Sometimes TrP-referred pain will clear up following correction of these perpetuating factors alone.

Because multiple mandibular elevator muscles develop interacting TrPs, it can be helpful to start with the combined release of all masticatory elevator muscles before addressing the temporalis individually.

Spray and stretch: The supine position is preferable. The patient allows the jaws to relax. With one hand, the operator takes up slack in the temporalis muscle by pulling upward on the muscle. With the other hand, vapocoolant spray is applied bilaterally from the attachment at the coronoid process upward over the entire muscle and all referred pain areas. The patient's eyes should be protected with dry cotton swabs. After setting aside the spray, the operator applies upward traction on the superior and posterior portions of the muscle to passively elongate the fibres. Then the patient inhales, opening the mouth as far as is comfortably possible to further elongate the muscle. The patient exhales and allows the mouth to close. The stretching phase is repeated until no further gain in range of motion occurs. Spray should always be applied bilaterally, even if only one side is symptomatic.

TrP pressure release, postisometric relaxation, and reciprocal inhibition through voluntary mouth opening are all effective direct manual techniques.

Joint play should be restored when it is restricted.

Trigger Point Injection

⚠ Safety Notice: Procedures described on this page involve structures in close proximity to major vessels or neurovascular bundles. This page is intended for qualified clinicians. Always identify relevant anatomy before proceeding. This site is not validated for clinical use — see the site disclaimer.

Before injecting, eliminate as many TrPs as possible through spray and stretch and manual techniques. Release any masseter TrP tension first (see above).

The lower jaw may be held partly open to locate the TrP precisely. Use a 2.5 cm (1-inch), 23- or 24-gauge needle directed upward between the fingers. A 27-gauge needle is too flimsy unless the fast-in, fast-out Hong technique is used. Inject with 0.5% procaine without epinephrine; alternatively, 1% lidocaine in 1.8 ml dental syringes. Injecting the midfibre central TrP is usually more effective than injecting the corresponding attachment TrP — inject both if necessary for complete relief.

Immediately after injection, apply maximal passive stretch with spray bilaterally. Follow with a hot pack and then active jaw range of motion. If opening is still restricted, repeat spray and stretch after rewarming.

Other Considerations

Therapy of the temporalis is not complete until all active TrPs in the upper trapezius and SCM have also been inactivated — these can indirectly restrict mandibular opening and maintain the temporalis TrPs as satellites. When treatment is unsuccessful or short-lived, also check for excessive tension in the suprahyoid and infrahyoid muscles.

When the temporalis and other masticatory muscles are involved with TrPs, they are usually involved bilaterally — because the mandible is connected across the midline, one side cannot be treated without an effect on the other.

Patient Education

Temporalis Self-Stretch Exercise

The patient opens the mouth to the comfortable fully open position. With fingers spread apart, firm upward pressure is applied just above the temples and over the ears, stretching the temporalis muscle while taking in a long full breath to augment muscle relaxation. A hot pack over the temple and face for 10–15 minutes before this exercise (or a wool scarf for neutral warmth) helps prepare the muscle. Practise daily.

Active-Resistive Mouth-Opening Exercise

The patient lightly resists opening of the mouth (with two fingers below the chin) for a few seconds, then actively opens as far as comfortable. This reciprocal inhibition technique overcomes restricted motion. For patients with TM joint inflammation or disc displacement with reduction: use tongue position on the palate to control the amount of opening and avoid the painful click.

If the posterior fibres are involved and the mandible deviates during opening: place one hand against the contralateral maxilla and the other against the ipsilateral mandible, and push the lower jaw away from the side toward which it deviates while actively assisting the motion. Restore the mandible gently before releasing pressure.

Habit Modification

  • Stop chewing gum, eating caramels, chewing tough meat, cracking nuts or ice with the teeth
  • Stop bruxism — a night guard or occlusal splint with a flat occlusal plane keeps the teeth a few millimetres apart during sleep and can relieve bruxism; also use during prolonged cervical traction
  • Tongue resting position: the tongue rests at the roof of the mouth (the position of the letter "N"), teeth slightly apart, not clenched
  • Avoid cold drafts directly on the temple — wear a night cap, hood, or scarf; avoid wind through open car windows when fatigued
  • During prolonged dental procedures: take breaks to go through several cycles of active jaw range of motion; apply occasional vapocoolant over the muscle while the mouth is fully but not forcibly open
  • Check and correct body asymmetry (leg length inequality, hemipelvis) which may activate neck muscles that in turn perpetuate masticatory TrPs

Systemic Check

Check for reduced thyroid function, folic acid deficiency, other metabolic disorders, and nutritional deficiencies — any of these may increase neuromuscular irritability and perpetuate masticatory muscle TrPs.

Satellite Trigger Points

The temporalis is associated with TrPs in:

  • Muscle:Masseter — ipsilateral deep division; most commonly co-involved; deep masseter tautness can entrap venous drainage from the temporalis
  • Muscle:Sternocleidomastoid — key TrP source for temporalis satellite activation
  • Muscle:Trapezius (upper) — key TrP source; inactivating the upper trapezius TrP has been shown to inactivate a satellite temporalis TrP
  • Contralateral temporalis — involvement is usually bilateral through the shared mandibular connection
  • Muscle:Medial_Pterygoid and Muscle:Lateral_Pterygoid — less commonly involved; sometimes bilaterally

References

  • Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 9.
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