-Attaching onto the internal surface of the mandible
The insertion of the medial pterygoid joins the masseter. The medial pterygoid pretty much mirrors the masseter but on the inside of the mandible. Together these two muscles form a sling that elevates the jaw.
The medial pterygoid elevates the mandible and contralaterally deviates the mandible, meaning it pulls the mandible towards the opposite side of the body, important for chewing.
The lateral pterygoid- Superior & Inferior Head
The inferior head attaches from the lateral side of the same process as the medial pterygoid attaches to onto the neck of the mandible.
The superior head attaches from the greater wing of the sphenoid to the capsule and disc of the temporomandibular joint.
The lateral pterygoid protracts the mandible, helping in opening the jaw, unlike the other 3 muscle of mastication that closes the jaw. It also creates contralateral deviation of the mandible- moving the jaw towards the opposite side.
The superior head helps draws the disc forward along with the mandible. So that the disc and mandible move together when the jaw is opened.
Isn’t that exciting that these two heads have to work together to allow the disc and mandible to draw forward for efficient movement.
Dysfunction or imbalance can cause the disc and mandible to track out of sync, and the disc can become displaced, this can cause inflammation, pain and be accompanied by clicking.
Temporomandibular joint syndrome/ dysfunction is an article all to itself.