Lateral Pterygoid

The Lateral Pterygoid is a facial muscle.

Anatomical Attachments:

• Origin: The lateral pterygoid has two heads. The upper head attaches to the greater wing of the sphenoid bone and the lower head attaches from the surface of the lateral pterygoid plate of the sphenoid bone.
• Insertion: Attaches to the anterior neck of the mandibular condyle and the capsule of the Temporomandibular joint (TMJ).

Action: This muscle of mastication extends the mandible, draws the articular disc forward and aids in the rotation movement while chewing.

Synergist: Digastric, Suprahyoid, Masseter, and Temporalis, and Medial Pterygoid.

Nerve Supply: Mandibular branch of the Trigeminal nerve (Cranial nerve V).

Nerve Entrapment: Entrapment of the buccal nerve leads to paresthesia of the cheek and the buccal mucosa. Entrapment syndrome of the chorda tympani portion of the lingual nerve, which may be entrapped by the medial pterygoid, must be differentiated from triggers in the platysma that may cause paresthesia. Since the buccal nerve is a division of the trigeminal nerve (Cranial nerve V), it may be observed with Bell’s palsy, therefore, if there is a hemiparalysis, consider Bell’s palsy. Paresthesia with no facial droop, consider entrapment or triggers in the platysma. With pain and hypersensitivity, consider trigeminal neuralgia or triggers within the SCM.

Vascular supply: Pterygoid branch of the maxillary artery.

• Primary: The pain refers deep into the Temporal mandibular joint (TMJ) and the maxillary sinus region.
• Satellite or associated triggers: Medial Pterygoid, Masseter, Posterior Temporalis, and Sternocleidomastoid.

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Trigger Point Signs and Symptoms: Pain in the TMJ region, moderate drainage from the maxillary sinus, ringing in the ears, pain while chewing, clicking or locking of the jaw.

Trigger Point Activating and Perpetuating Factors: Persistent chewing, gnashing or grinding of the teeth (bruxism); additionally Travell and Simon note that playing a wind instrument or cradling a violin are actions which may perpetuate TrPs.

Differential Diagnosis: Temporomandibular Joint Disorder (TMD), Mandibular dislocation or fracture, Sinusitis, Trigeminal Neuralgia, (Segmental, Subluxation, Somatic dysfunction) C2 radiculopathy or neuropathy, Muscular Dystrophy, Tetanus, Bruxism, Systemic infections or inflammation, Nutritional inadequacy, Metabolic imbalance, Toxicity, Side effects of medication.

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