The inner jaw muscle
Medial pterygoid · musculus pterygoideus medialis
A deep muscle on the inside of the jaw that mirrors the masseter.
What it does
The medial pterygoid runs from the base of the skull to the inner surface of the angle of the jaw. With the masseter on the outside, it forms a muscular sling around the jaw angle that closes the mouth and helps grind food side to side.
Surprising fact
The masseter and medial pterygoid together cradle the angle of the jaw like a hammock, one on each side of the bone.
Why it matters
Dentists sometimes have to pass a needle close to this muscle when numbing the lower teeth, and a stiff jaw afterwards can come from irritating it.
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.