Lateral Pterygoid
Mastication · Head & Neck
The lateral pterygoid is a short, thick, two-headed muscle of mastication set deep in the infratemporal fossa, oriented almost horizontally. Its superior head arises from the greater wing of the sphenoid and its inferior head from the lateral surface of the lateral pterygoid plate, and the two converge to insert on the neck of the mandible at the pterygoid fovea and onto the articular disc and capsule of the temporomandibular joint. Uniquely among the mastication muscles, its principal action is to protract and depress the mandible, opening the jaw, and alternating contraction produces the side-to-side grinding of chewing. It is supplied by the mandibular division of the trigeminal nerve (CN V3).
Origin, Insertion, Action & Nerve
Origin
Superior head: greater wing of sphenoid; Inferior head: lateral surface of lateral pterygoid plate
Insertion
Neck of mandible (pterygoid fovea), articular disc and capsule of TMJ
Action
Protracts and depresses mandible (opens jaw); contralateral grinding movements
Nerve
Mandibular division of trigeminal nerve (CN V3)
Attachments explained
The Lateral Pterygoid is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Superior head: greater wing of sphenoid; Inferior head: lateral surface of lateral pterygoid plate
Insertion
Neck of mandible (pterygoid fovea), articular disc and capsule of TMJ
Action & function
When the Lateral Pterygoid contracts, it produces the following movements: Protracts and depresses mandible (opens jaw); contralateral grinding movements.
As part of the Mastication group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Lateral Pterygoid receives its nerve supply from the Mandibular division of trigeminal nerve (CN V3).
Because a muscle can only contract when its nerve is intact, injury to the Mandibular division of trigeminal nerve can weaken or paralyse the Lateral Pterygoid, impairing the movements it normally produces (protracts and depresses mandible (opens jaw)). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Lateral Pterygoid (the OIANS method)
Single out the lateral pterygoid as the odd one out of the mastication group: while the others close the jaw, its horizontal pull on the neck of the mandible protracts and depresses it to open the mouth. Its attachment to the articular disc explains why it also guides the disc forward as the joint opens, a detail that links the muscle directly to temporomandibular joint mechanics.
Remember the two heads by their opposite bony origins, the greater wing of the sphenoid above and the lateral pterygoid plate below, both converging on the mandibular neck. Note that its contralateral grinding action pairs it with the medial pterygoid, and that it too is supplied by the mandibular division of the trigeminal nerve (CN V3).
Frequently asked questions
Where is the Lateral Pterygoid located?
The Lateral Pterygoid is a muscle of the Mastication group, located in the Head & Neck.
What is the origin of the Lateral Pterygoid?
Superior head: greater wing of sphenoid; Inferior head: lateral surface of lateral pterygoid plate
What is the insertion of the Lateral Pterygoid?
Neck of mandible (pterygoid fovea), articular disc and capsule of TMJ
What movements does the Lateral Pterygoid produce?
Protracts and depresses mandible (opens jaw); contralateral grinding movements
What nerve supplies the Lateral Pterygoid?
Mandibular division of trigeminal nerve (CN V3)
Is the Lateral Pterygoid free to study in OIANS?
The Lateral Pterygoid is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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