 Here everybody, Dr. O here. In this video we're going to cover all the muscles of mastication, mastication meaning chewing. In a 100 level anatomy class I'm usually just going to focus on the temporalis and the masseter, but I do want to explain a couple more that have some pretty critical roles. Let's start with those two. Temporalis muscles you can see here over the temporal bone and the masseter bone, which masseter muscles are that connects the upper and lower jaw, maxilla and mandible. They're both going to be involved in elevating the mandible. They play a big role in chewing, closing your mouth when you're chewing. Opening your mouth primarily just gravity does that, so relaxation of these muscles will open your mouth. If you want to feel them, I like to put my fingers here and my thumbs to my upper and lower jaw and just clench my teeth and you feel the temporalis and masseter muscles pop out. That's a good way to kind of get a feel for what they do and when they do it. So the temporalis, its primary function is to elevate the mandible. It does also play a role in retraction of the mandible, so bringing the mandible back a little bit. With the temporalis, masseter really just elevates the mandible, extremely powerful, pound for pound, one of the if not the strongest muscle in your body. So that's the temporalis and the masseter. Then we have the buccanator or buccanator, which basically means trumpeter. Its job is to compress the cheek. So if you were blowing into a horned instrument or blowing up a balloon, I guess that would matter, but it's role in mastication. It compresses the cheeks against the teeth when you're chewing. So it makes your teeth way more functional. That's the temporalis, the masseter, and then the buccanator muscle, which you see all those because they're very superficial. But I also want to talk about the medial and lateral pterogoids. So these are going to be deep muscles there and way back in the mouth attached to the sphenoid bone. So their job is going to be primarily to protract the mandible. So to jut the mandible out, so when you're chewing, it isn't just elevation and depression. It's also mandibles moving forward backwards and side to side, which the pterogoids, so they protract the mandible, but also move the mandible medial and laterally. Think about that kind of grinding action that can occur as the mandible goes forward, backward, side to side. So the forward movement and side to side movement, it's the pterogoid muscles. These muscles get super tight in a lot of people that have chronic like TMJ issues. I've had to go in and do a lot of pterogoid massages, you know, you glove up, you make sure they don't bite you and you have to get real deep in there. But it can be a game changer for a lot of people that have TMJ symptoms. So that is the temporalis and masseter, the two primary muscles of mastication. Then we have that buccanator and these pterogoids and the role that they play in chewing, which is elevation of the mandible is closing the mouth, depression of the mandible is opening it. Then we have protraction and retraction moving forward and backwards, and then some gliding side to side as well with chewing. Okay, I hope this helps. Have a wonderful day. Be blessed.