Lateral pterygoid

The Lateral Pterygoid (also known as the external pterygoid) is a muscle of mastication and is primarily responsible for opening the jaw and moving it from side to side. It is one of the four muscles of mastication, the others being the medial pterygoid, masseter, and temporalis.

Anatomy

The lateral pterygoid is a short, thick muscle that originates from two heads. The upper or superior head originates from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. The lower or inferior head originates from the lateral surface of the lateral pterygoid plate of the sphenoid bone. The two heads converge and insert into the neck of the mandible and the articular disc of the temporomandibular joint (TMJ).

Function

The primary function of the lateral pterygoid is to pull the condyle of the mandible forward, causing the jaw to open. It also moves the jaw from side to side and assists in protrusion and retrusion of the mandible. The lateral pterygoid is the only muscle of mastication that assists in opening the jaw, while the other three muscles primarily function to close the jaw.

Clinical Significance

Dysfunction of the lateral pterygoid can lead to several conditions, including temporomandibular joint disorder (TMD), bruxism (teeth grinding), and orofacial pain. Treatment typically involves physical therapy, medication, and in some cases, surgery.

See Also

• Medial Pterygoid
• Masseter
• Temporalis
• Muscles of Mastication
• Temporomandibular Joint

References

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