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TMJ and Muscles of Mastication

Original Editor - Ewa Jaraczewska based on the course by Micaela Weinberg

Top Contributors - Ewa Jaraczewska, Jess Bell and Tarina van der Stockt  

Introduction

Understanding the anatomy, pathological changes and palpation techniques for the muscles of mastication (masseter, temporalis, medial and lateral pterygoid) is essential when assessing and treating temporomandibular dysfunction. Dysfunction in these muscles can create compensatory patterns that extend beyond the local tissues of the jaw. This page describes the connections between the muscles of mastication and various structures and body regions.

Function of the Muscles of Mastication

The main mandibular movements during mastication are elevation, depression, protrusion (protraction), retraction and side-to-side movements.[1]

Referral Patterns of the Muscles of Mastication

The referral patterns of the muscles of mastication are consistent and diagnostically important.[2]

Masseter: the anterior fibres tend to refer more superiorly toward the forehead and upper teeth, while the posterior fibres refer to the temporomandibular joint itself and the ear region.[2]

Temporalis: the temporalis refers across the temple, into the teeth of the upper jaw, and can create a band-like tension across the entire side of the head. The anterior fibres refer primarily to the front teeth and forehead, while the middle and posterior fibres create the characteristic temporal headache.[2]

Pterygoid muscles: the lateral pterygoid refers to the maxilla and temporomandibular joint region. It can also contribute to joint clicking and limited opening. The medial pterygoid refers pain to the tongue, throat, and hard palate, as well as behind the temporomandibular joint and into the ear.[2]

Asymmetrical Development of the Muscles of Mastication

Unilateral chewing patterns[3] can lead to asymmetrical development in the muscles of mastication. These patterns may develop from pain avoidance, dental issues,[4] or habitual preference. The overused side hypertrophies—the muscle fibres become shortened and tight, contain multiple trigger points, and have reduced elasticity.[3] The underused side often becomes hypotrophic and weak, with poor motor control and reduced endurance.[5] This asymmetry creates mechanical challenges for a joint system that requires coordinated bilateral function. The hypertrophic side generates greater force and creates unequal compressive forces through the joint.[3] Weakness on the other side can lead to deviation during opening and closing. Over time, this pattern may contribute to altered joint loading patterns associated with disc displacement.

Capsular Restriction vs Muscular Symptoms

Capsular adhesions of the TMJ increase resistance during jaw movement, causing the muscles of mastication to work harder. This increased workload can lead to muscle fatigue, decreased masticatory efficiency, trigger point formation, muscular hyperactivity, and, eventually, hypertrophy.[6] Masseter and temporalis are the primary elevators and experience the greatest functional demand under these conditions. Therefore, capsular mobility testing must be included in the assessment, even when the presenting complaint is purely muscular.

Temporalis Tendon and Mechanical Stresses

The temporalis tendon can develop tendinopathy at its insertion on the coronoid process.[7] During clenching, the temporalis contracts with significant force for prolonged periods. These sustained isometric contractions create mechanical stress at the insertion.[8] This can present as thickening of the tendon, loss of the normal fibrillar structure, and the development of adhesions between the tendon and surrounding tissues.[9]

Muscles of Mastication and Eustachian Tube Function

The muscles of mastication are linked with the Eustachian tube via the tensor veli palatini muscle. Tensor veli palatini opens the Eustachian tube during swallowing, chewing and yawning.[10] This muscle shares fascial and functional connections with the medial pterygoid through the pterygoid hamulus and pterygomandibular raphe.[11] [12] Hypertonicity or trigger points in the medial pterygoid can alter the mechanical advantage of the tensor veli palatini, potentially compromising its ability to effectively open the Eustachian tube.

TMJ and Fascial Connections

Myofascial chains

The temporomandibular joint sits at the superior end of three major myofascial continuities that connect it to distant body regions. These fascial connections may explain why jaw dysfunction can arise from and contribute to problems far removed from the head and neck.[13][14]

Munhoz et al.[15] explain how postural stability relies on interconnected muscle chains, where localised postural changes cause nearby muscles to lengthen or shorten.

In another study, Munhoz et al.[16] found that patients with severe temporomandibular disorder (TMD) symptoms had a tendency towards forward positioning of the head and shoulders.

Lee et al.[17] report that flattening of the plantar arch can significantly impact overall body posture and muscle chain activity, including the masseter and temporalis muscles. They note that flat foot (pes planus) stimulates mechanoreceptor neurons in the foot, which initiates a compensatory chain reaction that adjusts head and neck position and shifts the body's centre of gravity.

Muscles of Mastication and the Autonomic Nervous System

Higher stress levels have been linked with TMD-related pain.[18] This relationship may be associated with changes in autonomic nervous system function. Both TMD and bruxism (repetitive masticatory muscle activity characterised by clenching or grinding of the teeth) have been associated with altered autonomic regulation, including heightened sympathetic activity and diminished parasympathetic function.[19][20] This autonomic dysregulation may play a contributory role in TMD-related pain.

Palpation and Soft Tissue Mobilisation Techniques for the Muscles of Mastication

Table 1 describes palpation and specific soft tissue mobilisation (SSTMS) techniques for the muscles of mastication.[9]

Table 1. Palpation and specific soft tissue mobilisation (SSTMS) techniques for the muscles of mastication
Muscle of Mastication Patient position Therapist position Technique
Masseter For palpation and SSTMS: sitting and supine The therapist faces the patient, standing on the opposite side of masseter being assessed/treated The therapist places their thumb inside the patient's mouth on the inside of the bottom teeth. Their index and middle fingers are placed externally on the outside of the face over the masseter. The therapist uses their other hand to stabilise the patient’s head. The masseter is an extraoral muscle and cannot be palpated from inside the mouth.

Points to remember: treat along the whole muscle belly; some parts may be thickened, and others may have trigger points; always treat what you find on assessment; treat into the angle of the mandible.

Temporalis For palpation and SSTMS: sitting and supine The therapist stands on the opposite side of the temporalis tendon being assessed/treated Temporalis tendon: the therapist places their thumb inside the patient's mouth to perform medial deep transverse frictions on the tendon in the medial aspect of the coronoid process. The therapist uses their other hand to stabilise the patient’s head.

Temporalis muscle: the therapist performs SSTMS on the temporalis muscle using their index and middle fingers, whilst the other hand stabilises the patient's head. Points to remember: this muscle is easier to treat in supine, although the anterior fibres can be accessed easily in sitting.

Medial pterygoid For palpation and SSTMS: sitting and supine The therapist stands next to the patient’s head Medial pterygoid: the patient opens their mouth fully and the therapist places their thumb/index finger on the underside of the back of the tongue. The therapist strokes their finger towards the tip of the patient's tongue.


Pterygomandibular raphe: the patient opens their mouth fully and the therapist traces the muscle vertically between the top and bottom back teeth. The therapist moves their thumb along the entire fascial band (superior to inferior).

Clinical Implications

The muscles of mastication can develop pathology in response to mechanical demands, postural patterns, breathing dysfunction, and the state of the nervous system. But they also provide the pathway for change to occur. Clinical management may include manual therapy techniques, motor control training, and approaches that address contributing factors such as posture, breathing patterns, and stress. A multimodal approach that considers the broader context of the musculoskeletal and nervous systems may help improve temporomandibular function and patients' quality of life.

Resources

References

  1. ↑ Basit H, Tariq MA, Siccardi MA. Anatomy, head and neck, mastication muscles.Study Guide from StatPearls Publishing, Treasure Island (FL), 05 Jun 2023
  2. ↑ 2.0 2.1 2.2 2.3 Fernández-de-Las-Peñas C, Galán-del-Río F, Alonso-Blanco C, Jiménez-García R, Arendt-Nielsen L, Svensson P. Referred pain from muscle trigger points in the masticatory and neck-shoulder musculature in women with temporomandibular disorders. The Journal of Pain. 2010 Dec 1;11(12):1295-304.
  3. ↑ 3.0 3.1 3.2 Kowalska K, Machorowska-Pieniążek A. Mandibular Lateral Displacement in Growing Patients: Etiopathogenesis, Prophylaxis, and Early Treatment—A Literature Review. Journal of Clinical Medicine. 2025 Nov 14;14(22):8090.
  4. ↑ Beltrami F, Kiliaridis S, Antonarakis GS. Masseter muscle thickness before and after the correction of unilateral functional posterior crossbite in growing individuals: a prospective controlled clinical trial. European Journal of Orthodontics. 2025 Jan;47(1):cjae078.
  5. ↑ Pecci-Lloret MR, García-Sampedro CM, Guerrero-Gironés J, López-Jiménez E. Observational Study: Preliminary Evaluation of Nostril Narrowing in Relation to Unilateral Mastication. Journal of Clinical Medicine. 2025 Feb 17;14(4):1319.
  6. ↑ Kryeziu K, Loxha MP, Hajdari B, Salihu L, Rexhepi M, Alihajdaraj R, Stubljar D, Starc A. A systematic review on masticatory muscle activity of temporomandibular joint in patients with rheumatoid arthritis. Acta Odontologica Scandinavica. 2025 Dec 15;84:44959.
  7. ↑ Bressler HB, Markus M, Bressler RP, Friedman SN, Friedman L. Temporal tendinosis: A cause of chronic orofacial pain. Current Pain and Headache Reports. 2020 May;24(5):18.
  8. ↑ Iturriaga V, Fuentes F, Borchardt T. Tendinitis of the temporalis muscle: Differential diagnosis and treatment. A Case Report. Journal of Oral Research. 2016;5(2):82-6.
  9. ↑ 9.0 9.1 Weinberg M. TMJ and Muscles of Mastication Course. Physiopedia Plus, 2026.
  10. ↑ Ghadiali SN, Banks J, Swarts JD. Finite element analysis of active Eustachian tube function. Journal of Applied Physiology. 2004 Aug;97(2):648-54.
  11. ↑ Helwany M, Rathee M. Anatomy, head and neck, palate.Study Guide from StatPearls Publishing, Treasure Island (FL), 05 Jun 2023
  12. ↑ El Haddioui A, Bravetti P, Gaudy JF. Anatomical study of the arrangement and attachments of the human medial pterygoid muscle. Surgical and Radiologic Anatomy. 2007 Mar;29(2):115-24.
  13. ↑ Hegab A. TMJ and Posture, Yes it’s All Connected: The Chain Theory of Body Linkage. Journal of Dental Health, Oral Disorders & Therapy. 2015 Jan 1.
  14. ↑ Findley, T. Second International Fascia Research Congress. International Journal of Therapeutic Massage & Bodywork: Research, Education, & Practice, 2009; 2(2):1-6.
  15. ↑ Munhoz WC, Marques AP. Body posture evaluations in subjects with internal temporomandibular joint derangement. Cranio. 2009 Oct;27(4):231-42.
  16. ↑ Munhoz WC, Marques AP, de Siqueira JT. Evaluation of body posture in individuals with internal temporomandibular joint derangement. Cranio. 2005 Oct;23(4):269-77.
  17. ↑ Lee YJ, Park JH, Lee SJ, Ryu HM, Kim SK, Lee YJ, Yoon HM, Jang SH, Song CH, Kim CH. Systematic review of the correlation between temporomandibular disorder and body posture.Journal of Acupuncture Research 2017;34(4):159-168.
  18. ↑ Kakko N, Suominen A, Somero A, Tulppo M, Lahti S, Pohjola V, et al. Association between cardiovascular autonomic function and temporomandibular disorders. J Oral Rehabil. 2025 Nov;52(11):1894-1905.
  19. ↑ Navarro-Rico C, Fricke-Comellas H, Heredia-Rizo AM, Díaz-Mancha JA, Rosado-Portillo A, Fernández-Seguín LM. Short-Term Effects of Visceral Manual Therapy on Autonomic Nervous System Modulation in Individuals with Clinically Based Bruxism: A Randomised Controlled Trial. Dentistry Journal. 2025 Jul 16;13(7):325.
  20. ↑ Cairns BE. The contribution of autonomic mechanisms to pain in temporomandibular disorders: A narrative review. J Oral Rehabil. 2022 Nov;49(11):1115-1126.
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