View source for Muscle:Buccinator

'''Buccinator''' is the principal muscle of the cheek, forming the lateral wall of the oral cavity. Its trigger points (TrPs) produce local cheek pain and a deep subzygomatic ache in the jaw that is one of the most reliably misdiagnosed presentations in myofascial pain — the combination of jaw pain and swallowing difficulty leads directly to a working diagnosis of temporomandibular joint (TMJ) syndrome in the majority of cases. Activation is commonly associated with ill-fitting dental appliances or prolonged orthodontic treatment.

== Anatomy ==

The buccinator is the principal muscle of the cheek forming the lateral wall of the oral cavity:

* '''Anteromedially''' — fibres converge toward the angle of the mouth, where they divide and become continuous with the fibres of the [[Muscle:Orbicularis_Oris|orbicularis oris]]
* '''Laterally''' — attaches chiefly to the pterygomandibular raphe, a tendinous inscription that also anchors the superior pharyngeal constrictor
* '''Posterolaterally''' — some fibres attach to the outer surfaces of the alveolar processes of the maxilla above and the mandible below

The muscle is pierced by the parotid duct. It lies within the superficial fascia of the cheek.

'''Innervation:'''
* Motor — facial nerve (cranial nerve VII), buccal branch
* Sensory (skin and mucous membrane of the cheek) — buccal nerve branch of the trigeminal nerve (cranial nerve V)

'''Primary actions:'''
* Movement of food about the mouth — works in interplay with the tongue to keep food on the occlusal surface during chewing; contraction decreases the size of the oral cavity
* Whistling and blowing a wind instrument
* Swallowing
* Facial expression (paired buccinator muscles)

'''Functional unit:''' The tongue works with the buccinator muscles to control food during chewing. The muscles of exhalation cooperate closely with the buccinators during wind instrument playing. The orbicularis oris frequently works in concert with the buccinators.

== Referred Pain Pattern ==

TrPs in the buccinator refer:

* '''Local pain''' in the cheek (at the site of the TrP in mid-cheek)
* '''Deep subzygomatic ache''' in the jaw — felt as pain deep to the cheek, below the zygomatic arch

This deep aching jaw pain, combined with difficulty swallowing (see Symptoms below), is the presentation that most commonly leads to misdiagnosis as TMJ syndrome.

== Activation and Perpetuating Factors ==

* '''Ill-fitting dental appliances''' — the primary activating mechanism documented in the literature; orthodontic appliances and mandibular splints can activate buccinator TrPs directly
* '''Prolonged orthodontic treatment''' — activation may occur near the end of orthodontic care, where shifting TrP activity between latent and mild active states can account for variable symptoms
* '''Masticatory muscle dysfunction''' — TrPs in the masticatory muscles that cause trismus or restricted opening overload the buccinator during chewing
* '''Sustained chewing''' — gum chewing, nail biting, or tough foods

== Clinical Examination ==

=== Symptoms ===

* '''Local cheek pain''' at or near the TrP
* '''Deep subzygomatic jaw ache''' — the dominant complaint; may be described as "jaw pain" or "tooth pain" pointing to the buccal region
* '''Perceived difficulty swallowing''' — the patient reports difficulty swallowing, although the swallowing movement appears normal on observation; this is a referred autonomic effect of the TrP, not a structural swallowing disorder
* Subzygomatic jaw pain aggravated by chewing

=== Patient Examination ===

* Inspect for dental appliances, orthodontic hardware, or occlusal splints
* Assess jaw opening — restricted opening with masticatory co-involvement
* TM joint dysfunction should be formally ruled out before attributing jaw pain to buccinator TrPs

For the full TMJ screening protocol see [[Pain:TMJ_Screening_Examination|TMJ Screening Examination]].

=== Trigger Point Examination ===

TrPs are found in mid-cheek, halfway between the angle of the mouth and the ramus of the mandible:

# Use '''pincer palpation''' with one gloved finger inside the mouth and one outside
# Find a taut band running in the direction of the muscle fibres (horizontally, from the angle of the mouth toward the ramus)
# Identify the band by sliding the inside finger up and down against the counterpressure of the outside finger, '''across''' the direction of the fibres, while squeezing gently
# Augment TrP tenderness by pressing the cheek outward — this places the buccinator on increased tension
# '''Snapping palpation''' of the band at the tender active TrP produces a '''painful, palpable, and usually visible local twitch response''' — this is readily elicited in this superficial muscle and is one of the most reliable diagnostic signs

'''Infrared thermography''' (where available): The region over an active buccinator TrP may show a temperature ≥1°C above the surrounding tissue.

=== Nerve Entrapment ===

No nerve entrapments have been observed due to active TrPs in the buccinator.

== Differential Diagnosis ==

The buccinator is among the most diagnostically treacherous muscles in the head and neck. Its TrPs reliably produce the clinical triad of jaw pain, swallowing difficulty, and cheek tenderness — precisely the features used to diagnose TMJ syndrome.

* '''TMJ syndrome / TMJ dysfunction''' — the dominant misdiagnosis; distinguish by:
** Active TrP confirmed by taut band, focal tenderness, and local twitch response on snapping palpation
** Reproduction of the patient's familiar subzygomatic pain on bidigital compression of the TrP
** Normal swallowing movement despite the patient's perception of difficulty
** Response to TrP treatment (electrotherapy, dry needling, or pressure release) — full symptom resolution without any joint intervention
* '''Dental pain / odontogenic pain''' — deep jaw ache may be attributed to a tooth; distinguish by absence of dental pathology on examination and radiography, and by TrP reproduction of pain on palpation
* '''Parotid gland pathology''' — the parotid duct pierces the buccinator; parotid swelling, pain with eating (Stensen's duct obstruction), and fever distinguish parotid disease
* '''Tension headache''' — cheek pain attributed to tension headache without recognition of the facial muscle source

== Treatment ==

=== Trigger Point Release ===

==== Spray and Stretch ====

Spray and stretch of the buccinator is '''more effective than for the orbicularis oculi''' because the muscle can be adequately stretched:

# Stretch the muscle by pressing the cheek outward with one finger
# While maintaining tension, apply vapocoolant spray over the cheek
# '''Postisometric relaxation''' and '''trigger point pressure release''' can also be effective using this approach
# If the patient has asthma or another respiratory condition, substitute ice stroking for the spray

==== Electrotherapy ====

Electrotherapy has been reported as effective for buccinator TrPs (Curl, 1989 — see Case Report in Travell & Simons Vol. 1, Ch. 13):

* Electrodes placed on each side of the TrP — one inside and one outside the mouth
* 500 μA of 800 Hz direct current pulses, switched between negative and positive every 2 seconds
* Approximately 7 minutes per session
* Three treatments, each two days apart — full symptom resolution reported in the documented case

=== Trigger Point Injection ===

If noninvasive therapy produces unsatisfactory results:

# Hold the TrP in a pincer grasp between the fingers of the non-injecting hand
# Perform '''dry needling''' — the TrP is inactivated if local twitch responses are elicited by the needle
# Alternatively, inject with 0.5% procaine in isotonic saline using a 16 mm (5/8 inch), 25- or 26-gauge needle

The three most reliable diagnostic criteria, as used in the Curl case report, are: (1) a spot of focal tenderness, (2) in a taut band that, when compressed, (3) reproduces the patient's pain complaint. The local twitch response is the most discriminating and skill-demanding confirmatory criterion.

=== Corrective Actions ===

* '''Address dental appliances''' — ill-fitting splints, orthodontic hardware, or occlusal appliances should be assessed and adjusted; this is the most direct perpetuating factor
* Inactivate TrPs in the masticatory muscles ([[Muscle:Masseter|masseter]], [[Muscle:Temporalis|temporalis]], [[Muscle:Medial_Pterygoid|medial pterygoid]], [[Muscle:Lateral_Pterygoid|lateral pterygoid]]) that are overloading the buccinator
* Inactivate TrPs in other muscles referring pain to the same side of the face — [[Muscle:Sternocleidomastoid|sternocleidomastoid]], [[Muscle:Trapezius/Upper|upper trapezius]]
* Address parafunctional habits — gum chewing, nail biting, sustained clenching

== Satellite Trigger Points ==

* [[Muscle:Masseter|Masseter]] — the dominant co-involved masticatory muscle; shares the subzygomatic pain region
* [[Muscle:Temporalis|Temporalis]] — masticatory co-involvement
* [[Muscle:Zygomaticus_Major|Zygomaticus major]] — overlapping cheek and jaw pain region
* [[Muscle:Platysma|Platysma]] — secondary to SCM/scalene involvement; prickling jaw pain

== Related Pages ==

* [[Pain:FaceAndJaw|Face and Jaw pain region]] (coming soon)
* [[Pain:TMJ_Screening_Examination|TMJ Screening Examination protocol]] — essential before attributing jaw pain to buccinator TrPs
* [[Pain:Ear_and_TMJ|Ear and TMJ diagnostic algorithm]]
* [[Muscle:Masseter|Masseter]] — primary co-involved masticatory muscle
* [[Muscle:Zygomaticus_Major|Zygomaticus major]] — co-involved facial muscle; nasal arc referral
* [[Muscle:Platysma|Platysma]] — co-involved; prickling mandibular pain
* [[Muscle:Orbicularis_Oculi|Orbicularis oculi]] — co-involved; nasal and upper lip pain

== 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 13.
* Curl DD. Discovery of a myofascial trigger point in the buccinator muscle: a case report. ''J Craniomandib Pract'' 7(4):339–345, 1989.

[[Category:Muscle]]
[[Category:Vol1 Ch13]]
[[Category:Head and Neck]]