External
The masseter acts as the antagonist.
The antagonist for the mandible is the temporalis muscle. It is responsible for closing the jaw while the mandible is involved in opening the jaw.
The masseter muscle is the chewing muscle covering the angle of the mandible. During bilateral contraction, the muscle elevates the mandible, raising the lower jaw.
.. Masseter - prime mover of jaw closure - elevates the mandible ... External intercostals - with 1st rib fixed by scalene muscles - pull ribs toward one
The masseter muscle is lateral to the ramus of the mandible.
antagonist muscle
A antagonist muscle is a muscle that opposes the action of another muscle. The Triceps Brachii is the antagonist of the Biceps Brachii.
antagonist
The only mandible I know of is the lower jaw in many species. Sorry if I'm wrong.
the masseter muscle
The insertion of the temporalis muscle is on the coronoid process of the mandible.
The antagonist muscle opposes a movement, slows it down and returns the appendage to is natural position once the movement is complete. They work in conjunction with agonist muscles in creating a balanced movement and return.