The jaw-opening muscle
Lateral pterygoid · musculus pterygoideus lateralis
A deep jaw muscle that pulls the jaw forward and helps open the mouth.
What it does
The lateral pterygoid lies deep behind the cheek, running horizontally from the base of the skull to the neck of the jaw and the disc inside the jaw joint. It pulls the jaw forward and helps open the mouth wide, and its two sides take turns to swing the jaw side to side when you chew.
Surprising fact
It is the only one of the main chewing muscles that helps open the mouth rather than close it.
Why it matters
Problems with this muscle and the disc it pulls on are linked to the clicking and locking some people feel in their jaw joint.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.