Mastication muscle infection refers to inflammation and infection of one or more of the primary muscles involved in chewing—namely the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. When a pathogen (bacterial, viral, fungal, or parasitic) invades these muscles, it leads to myositis (muscle inflammation), abscess formation, pain, swelling, and impaired jaw movement. Although inflammatory muscle diseases can also be immune-mediated (such as masticatory muscle myositis), the focus here is on infectious processes. Early recognition and treatment are vital to prevent spread to adjacent fascial spaces and deeper neck structures MedlinePlusPMC.
Anatomy of the Masticatory Muscles
Structure & Location
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Masseter: A thick, rectangular muscle on the lateral side of the mandible.
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Temporalis: A fan-shaped muscle filling the temporal fossa on the side of the skull.
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Medial Pterygoid: A quadrangular muscle on the medial (inner) aspect of the mandible.
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Lateral Pterygoid: A two-headed muscle situated deep in the infratemporal fossa. Wikipedia
Origin & Insertion
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Masseter: Originates from the zygomatic arch; inserts on the lateral surface of the mandibular ramus.
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Temporalis: Originates from the temporal fossa; inserts on the coronoid process and anterior border of the mandibular ramus.
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Medial Pterygoid: Originates from the medial surface of the lateral pterygoid plate and palatine bone; inserts on the medial mandibular ramus.
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Lateral Pterygoid: Superior head originates from the greater wing of the sphenoid; inferior head from the lateral pterygoid plate; both insert on the pterygoid fovea of the mandibular condyle Wikipedia.
Blood Supply
Primarily from branches of the maxillary artery—masseteric artery (masseter), deep temporal arteries (temporalis), pterygoid branches (pterygoids) Wikipedia.
Nerve Supply
All four muscles receive motor innervation from the mandibular division (V₃) of the trigeminal nerve:
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Masseteric nerve → masseter
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Deep temporal nerves → temporalis
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Medial and lateral pterygoid nerves → respective muscles Wikipedia.
Primary Functions
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Elevation of the mandible (closing the jaw)
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Protrusion (pushing the jaw forward)
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Retraction (pulling the jaw backward)
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Lateral excursion (side-to-side grinding)
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Stabilization of the mandible during speech
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Assisting swallowing by positioning the mandible NCBI.
Types of Mastication Muscle Infections
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Acute Infectious Myositis
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Rapid onset due to bacterial invasion (e.g., Staphylococcus aureus, Streptococcus spp.) with pain, swelling, fever.
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Chronic Infectious Myositis
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Slow progression (e.g., tuberculosis, actinomycosis) with granuloma formation and fibrosis.
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Viral Myositis
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Often due to influenza or enteroviruses; presents with diffuse muscle pain.
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Fungal Myositis
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Rare; seen in immunocompromised patients (e.g., Candida, Cryptococcus).
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Parasitic Myositis
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Caused by organisms like Trichinella spiralis; leads to muscle fiber invasion.
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Masticatory Muscle Abscess
Causes
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Dental infections (pericoronitis, pulpal necrosis) Wikipedia
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Mandibular fractures with contamination Wikipedia
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Post-operative infections after oral surgery
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Hematogenous spread from distant foci (e.g., endocarditis) PMC
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Tetanus toxin causing sustained spasm and secondary muscle damage
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Influenza virus leading to viral myositis MedlinePlus
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COVID-19 related myositis (documented case reports)
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Tuberculosis of the masticatory muscles PMC
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Actinomycosis extending from jaw abscess
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Trichinellosis via ingestion of undercooked meat PMC
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Dermatomyositis (infection-triggered flare) MedlinePlus
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Polymyositis (infection as precipitant) MedlinePlus
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Retrograde infection via parotid duct
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HIV/AIDS immunosuppression leading to opportunistic myositis
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Steroid therapy reducing immunity
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Diabetes mellitus predisposing to bacterial spread
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Malnutrition weakening local defenses
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Radiation therapy causing mucosal breakdown
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Animal bites transmitting anaerobic bacteria
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Iatrogenic inoculation (intramuscular injections) MedlinePlusPMC.
Symptoms
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Localized pain worsened by chewing
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Swelling over the jaw or temple area
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Tenderness on palpation
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Trismus (limited mouth opening) NCBI
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Fever and chills
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Malaise and fatigue
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Muscle weakness in jaw closure
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Erythema overlying skin
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Crepitus if gas-forming organisms present
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Dysphagia (difficulty swallowing)
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Odynophagia (painful swallowing)
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Otalgia (referred ear pain)
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Halitosis (bad breath) if abscess drains orally
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Enlarged lymph nodes in neck or submandibular region Wikipedia
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Headache
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Mandibular deviation on opening
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Facial asymmetry in swelling
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Weight loss secondary to poor oral intake
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Night sweats (in chronic infections)
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Elevated inflammatory markers (ESR, CRP) PMC.
Diagnostic Tests
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Complete blood count (CBC) – leukocytosis
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Erythrocyte sedimentation rate (ESR) – elevated
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C-reactive protein (CRP) – elevated PMC
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Blood cultures – identify bacteremia
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Ultrasound – detect fluid collections
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Contrast-enhanced CT scan – delineate abscess & deep spread
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MRI – show muscle edema and inflammation
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Needle aspiration – obtain pus for culture
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Gram stain & culture – identify bacteria
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Acid-fast bacilli stain – for mycobacterial infection
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Fungal cultures – for fungal pathogens
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Serology – viral myositis (e.g., influenza)
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Muscle biopsy – confirm myositis type
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Autoimmune panels – rule out dermato/polymyositis
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Electromyography (EMG) – assess muscle function
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Creatine kinase (CK) – elevated in muscle damage
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Monoclonal antibodies assay – for masticatory muscle myositis (2M fiber) vetneuromuscular.ucsd.edu
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Ultrasound-guided biopsy – precise tissue sampling
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PCR assays – viral or mycobacterial DNA
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Procalcitonin – marker for severe bacterial infection PMC.
Non-Pharmacological Treatments
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Warm compresses to reduce pain
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Cold packs to decrease swelling
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Gentle jaw stretching exercises NCBI
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Soft diet to minimize chewing
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Good oral hygiene to prevent spread
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Hydration to support healing
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Rest of the masticatory muscles
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Ultrasound therapy for deep heat
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Electrical muscle stimulation
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Massage therapy to improve circulation
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Physiotherapy for jaw mobilization
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Transcutaneous electrical nerve stimulation (TENS)
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Low-level laser therapy
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Acupuncture for pain relief
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Stress management (to reduce muscle clenching)
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Biofeedback for muscle control
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Dental splints/night guards NCBI
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Speech therapy if swallowing is affected
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Positioning pillows to avoid pressure on jaw
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Heat-moist towel packs
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Oral myofunctional therapy
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Infrared lamps
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Hydrocolloid dressings on extra-oral swelling
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Lymphatic drainage massage
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Guided imagery/relaxation techniques
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Dietary counseling for nutrition
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Avoidance of aggravating activities (e.g., gum chewing)
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Jaw rest appliances
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Magnetic therapy (adjunctive)
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Cold laser acupuncture PMC.
Drugs
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Amoxicillin-clavulanate (broad-spectrum antibiotic)
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Clindamycin (anaerobic coverage)
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Cephalexin (first-generation cephalosporin)
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Ceftriaxone (third-generation cephalosporin)
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Metronidazole (for anaerobes)
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Vancomycin (MRSA coverage)
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Linezolid (MRSA & VRE)
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Doxycycline (tick-borne pathogens, some atypicals)
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Levofloxacin (Gram-negative coverage)
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Piperacillin-tazobactam (broad coverage)
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Meropenem (severe infections)
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Itraconazole (fungal myositis)
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Amphotericin B (severe fungal)
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Albendazole (parasitic myositis)
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Prednisone (for immune-mediated component)
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Methotrexate (steroid-sparing in MMM) vetneuromuscular.ucsd.edu
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Azathioprine (immunosuppression)
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Intravenous immunoglobulin (IVIG) (autoimmune)
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Ibuprofen (NSAID for pain)
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Acetaminophen (analgesic & antipyretic) MedlinePlus.
Surgeries
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Incision and drainage of abscess (intraoral or extraoral) Wikipedia
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Wide debridement of necrotic muscle
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Myotomy (in chronic contracture)
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Coronoidectomy (to improve mouth opening)
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Mandibular osteotomy (for severe jaw deviation)
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Temporalis flap reconstruction (post-debridement)
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Microvascular free flap (for large defects)
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Neurectomy (in refractory spasm)
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Temporomandibular joint (TMJ) release
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Scar revision surgery (in chronic stages) Wikipedia.
Prevention Strategies
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Prompt dental care for infections
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Protective gear to prevent facial trauma
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Strict asepsis during oral procedures
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Immunizations (tetanus, influenza)
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Good glycemic control in diabetes
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Nutrition optimization
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Avoiding undercooked meat (prevent trichinellosis)
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Timely treatment of systemic infections
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Regular dental check-ups
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Sterile technique for intramuscular injections PMC.
When to See a Doctor
Seek medical attention immediately if you experience:
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Severe jaw pain with high fever
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Inability to open or close your mouth
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Rapidly spreading facial swelling
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Difficulty breathing or swallowing
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Signs of systemic infection (e.g., chills, confusion) PMC.
Frequently Asked Questions (FAQs)
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What causes mastication muscle infections?
Bacteria from dental infections or trauma often spread into chewing muscles, causing infection. -
Can viral infections affect chewing muscles?
Yes—viruses like influenza can invade and inflame these muscles. -
How is a masticatory muscle abscess treated?
Incision and drainage plus appropriate antibiotics usually resolve it. -
Is jaw stiffness always an infection?
No—trismus can result from TMJ disorders, but infection is likely when fever and swelling accompany stiffness. -
Are imaging tests necessary?
Often—CT or MRI helps locate abscesses and plan drainage. -
Can I treat it at home?
Home remedies (warm compress, soft diet) help comfort, but antibiotics and possible drainage are essential. -
How long does recovery take?
With prompt treatment, most resolve in 1–2 weeks; chronic cases may take months. -
Can it recur?
Yes—especially if underlying dental issues are not addressed. -
Are there risks of spread?
Without treatment, infection can extend into deep neck spaces, causing life-threatening complications. -
Do I need surgery?
If an abscess forms, surgical drainage is required. -
Can diabetes worsen it?
Poor blood sugar control increases infection risk and severity. -
What role do physiotherapy exercises play?
They help restore jaw mobility after acute inflammation subsides. -
Is masticatory muscle myositis the same as infection?
No—myositis can be immune-mediated without any infection. -
How do I prevent it?
Good dental hygiene, prompt treatment of oral infections, and avoiding facial trauma are key. -
When is hospitalization needed?
If you have high fever, airway compromise, or rapid spread of swelling, inpatient care is advised.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team Rxharun and reviewed by the Rx Editorial Board Members
Last Updated: April 24, 2025.
