Alright guys. In this video we’re going to talk about the muscles of the head and the neck. First thing we’re going to look at is the muscles of mastication or the chewing muscles. Now, remember that’s the muscles of mastication not masturbation. Alright so, the first thing we’re going to do, is we’re going to take a look here at the first muscle here. This is going to be the call to temporalis muscle. Now, the origin of the temporalis muscle is going to be the faucet temporalis on the temporal fossa and it insertion down here at the coronoid process on the ramus of the mandible. It’s action is to be able to elevate the mandible. Ok, so this is the temporalis muscle and just remember in general, it’s going to elevate the mandible. Then I’m going to take and turn this guy over here to this side. If you look at 38, this is the masseter muscle. There’s a superficial and a deep masseter, but this is just going to be our superficial masseter right here. And the masseter muscle just like the temporalis, it helps to be able to elevate the mandible. And you can tell that again because it’s origin is the zygomatic bone, it’s also the zygomatic arch too and then the insertion is right down here at the ramus of the mandible and angle the mandible. And they are going to elevates the mandible. If you look here, you can kind of see it. Here that’s 35 that’s the buccinator. Ok, that’s the buccinator and the buccinator is actually, what it does is it helps to be able to compress the contents of the cheek and to move the food towards the middle for chewing. And so this is the buccinator right there. Okay and then, I’m going to take, there is two more muscles that you can’t really see on this that are also part of the muscles of mastication, which is the lateral pterygoid and the medial pterygoid but they can’t be seen on this model. I guess now we’re going to take a look at the muscles of facial expression. So, first one is going to be this muscle right here, this is actually the frontal belly of the occipital frontalis right here. And then what I’m going to do here is going to kind of turn it up like that and you can see here this little connective tissues. It’s actually called aponeurosa It’s called the, it’s the galea aponeurotica or the epicranial aponeurosis and it connects the frontal belly with the occipital belly back here of the occipital frontalis. Alright, another muscle we’re going to take a look at right here, is going to be this one right here, wrapping all the way around the eye, It’s a sphincter, muscles 25 right here called the obicularis oculi. The obicularis oculi. And the obicularis oculi is responsible for being able to, for the squinting action. So, it’s being able to squint and blink the eyes, okay. That’s the obicularis occuli and then the occipital frontalis, the frontal belly it will actually pull the eyebrow up. And if you look here 34, this muscle right there, this muscle is going to be called the levator labii superiororis and what it does, is it elevates the upper lip. Now, there is a tiny little muscle that you can kind of see right here, that muscle right there next to the levator labii superiororis is called the zygomaticus minor, okay zygomaticus minor. It helps to be able to pull the upper lip, also kind of upwards and backwards to assist this muscle right here, which is called the zygomaticus major. And the zygomaticus major is actually going to draw the angle of the mouth upwards and backwards for smiling. And if you look here 30 coming across from this corner of the mouth right here all the way over here to this lateral fascia of the cheek is actually going to be called the risorius. And the risorius pulls the actual corner of the mouth laterally and so that helps would like the face of grimness, okay. Then if we look over here at 29, this is called the depressor anguli oris or they also call the triangularis, because it looks like a kind of shape, forms a triangle here. And that is designed to be able to pull the angle of the the mouth downward. Okay, so it kind of us to pull the angle of the mouth downward. Then I’m going to turn it in here and you got this muscle right there, and this is called the depressor labii inferioris and it basically it pulls the lower lip downward. So again, the depressor labii inferioris pulls the lip downward, the lower lip. So right here, is the mentalis and the mentalis is actually designed to be able to protrude the lower lip right. So helps to be able to kind of make that sad face, so protrudes the lower lip right there. So you see 28 right here, another sphincter there, kind of wrapping around the lips, right here. And this is actually gonna be called the orbicularis oris. That’s the orbicularis oris and it helps with being able to you know close the mouth and keep the mouth shut, okay. So that’s basically a sphincter muscle and that’s designed to be able to close the mouth, right. That’s the obicularis oris. And another muscle you can kind of see right up here, around the cartilage of the nose, the hyaline cartilage is called the transverse nasalis right there. So there’s the transverse nasalis. Alright, so now we’re going to cover a couple extra muscles here. So this is right here, it’s called the auricularis anterior, it kinda helps to draw the ear and the skins to ear forward. And then over here, we’re going to have the auricularis superior, kind of draws the ear and the skin of the ear upwards. And then, this is the auricular posterior back there and that’s going to draw the ear in the skin of the ear backwards. Alright guys, so now we’re going to take a look at the lateral neck muscles. So over here, we have this big, big, huge muscle. This is S.C.M. or the sternocleidomastoid. Now, the sternocleidomastoid has its origin situated here at the sternal end, here of basically the anterior surface of the manubrium. And then it also has this clavicular head here, that attaches to the medial third of the clavicle there. And then its insertion point is going to be over here at the mastoid process and a lateral part of the superior nuchal line. And its function is to be able to flex the neck and assist in basically the forceful inhalations. Now, we’re going to go ahead and turn over here the other lateral neck muscles. Alright guys, so now we’re going to take a look at the scalenes. So if you look here, this is going to be our anterior scalene right, here number 44. Then over here we’re going to have the middle scalene, which is 42. And now we’re going to the posterior scalene right here, which is going to be 43. And all of these guys function to be able to flex the neck and to be able to assist and inhalation. So now, we’re going to take a look at some of the posterior neck muscles. So if you look here number 45, this is called our levator scapulae. So, levator scapulaa, it’s actually going to be designed to be able to elevate the scapula alright. And if you look here number 19, this guy is going to be called the splenius capitis. This is a splenius capitis and it’s designed to be able to help extend the neck. And if you look here, this is called the semi spinalis capitis and it also helps to be able to extend the neck. So now we’re going to take a look at the trapezius. So if you look at the trapezius, here this trapezius has these fibers, they are these descending fibers of the trapezius. And this trapezius is actually more superficial than these muscles over here, that we talked about, the semi spinus capitis, splenius capitis and levator scapula. The trapezius because of its origin and insertion, it helps to be able to extend the neck and elevate the scapula. I want to give you guys another look at the trapezius muscle here. If you look here, this is the trapezius muscle all right here. And, what I wanted to show you is how you can tell it’s such a superficial muscle. I’m going to pull this part here out and you can actually see these layers, these muscles right underneath it right here. So you can see like we talked about with the other, the herald head. You can see here that this is the splenius capitis. You can see here the levator scapula and you get the rhomboids down here, that we’ll talk about in the future. I would again, the trapezius muscle it’s a very, very superficial muscle, all right. So that pretty much gives us everything we can know about the posterior neck muscles and a lot of neck muscles on this model. Alright guys, so now we’re going to take a look at another muscle that we can only see it on this model here. It’s this muscle right here and this is called the platysma. And what the platysma does that helps to be able to pull or depress the mandible down. So you can actually see, this is the platysma and you can see how it’s such a superficial muscle right here. And it’s lying over this part, it that has this pectoral fascia right there. That it actually originates on and then again insertion is the inferior border of the mandible there. Now we’re going to take a look at the suprahyoid muscles. So the suprahyoid muscles are going to be all the muscles here, above the hyoid bone all their insertion points are right there on the hyoid bone. So if you look here, we have two bellies of this muscle right? This is called the digastric but it’s called the anterior belly of the digastric. Then if you look here number 47, this muscle right there, this is called the digastric posterior belly. So the digastric anterior belly and the digastric posterior belly, they both help to be able to elevate the hyoid bone. Now if the hyoid bone is fix the digastric anterior belly can also depress the mandible too. So let’s come over here. So we look here guys, this is just the submandiblular salivary gland, but 49 right here, is going to be our mylohyoid. There’s another piece of the mylohyoid right there and then 50 is a geniohyoid. And we already said that 46 of the digastric anterior belly. And if you look here 48, 48 is going to be the stylohyoid muscle. And again all of these muscles, all the ones that I’ve mentioned all elevate the hyoid bone. The only thing that’s a little different, is that the digastric anterior belly can depress the mandible if the hyoid bone is fixed. Alright so now, I want to look at the infrahyoid muscles. So, the infrahyoid muscles are all the muscles below the hyoid bones and again these are going to depress. They’re going to pull that hyoid bone down. So then their insertion points will be there. So if you look right here 53, this is going to be the omohyoid, but it can be the superior belly, there’s an intermediate tendon that you can’t taste underneath the sternocleidomastoid, that connects the two bellies. Again, this is the omohyoid superior belly and this is the omohyoid inferior belly right here. And again, the omohyoid inferior belly and superior belly are connected to what’s called an intermediate tendon. We’re going to take another look here, I wanted to show you guys, you guys couldn’t see the intermediate tendon in between the superior omohyoid and the inferior omohyoid, but if I remove the sternocleidomastoid out of this. And so as you can see, you guys this structure right there, that’s the intermediate tendon. Again that’s what connects the two on the highway bellies together and while we’re here we can also see a couple other structures. If you look here number 26, 26 right there is actually going to be the anterior scalene, 25 is we middle scalene and 24 is going to be the posterior scalene. You can see the levator scapula, right there. And if you look over here, you guys can see their 20 is the digastric posterior belly. And see it also it attaches right there to the mastoid notch there. And over here is 21, 21 is there stylohyoid can attach the styloid process there. So that just gives you guys another view of these neck muscles. Alright the other infrahyoid muscle is going to be right here. This is called the sternohyoid muscle. The sternohyoid muscle. And then over here number 56, that’s actually going to be the sternothyroid. Okay so, that’s going to be the sternothyroid. And so we have sternothyroid. And we got the sternohyoid and then we got the omohyoid superior and inferior belly. And again all of those are infrahyoid muscles, meaning that they depress the hyoid bone. And all of these things were trying to depress and elevate the hyoid bone all play a role in phonation or voice production. Alright guys, it’s pretty much going to finish up everything that we talked about for the head and the neck muscles.