 So, this is a demonstration of the temporal region, the temporal muscle and the masseter muscle. This is the temporal region. The boundaries of the temporal region, superiorly and posteriorly, we have this line here. This is the superior temporal line. Anteriorly, we have the frontal bone and the zygomatic bone. Inferiorly, we cannot see, is the intratemporal crest of sphenoid and laterally we have this ridge of bone where my finger is located and that is the zygomatic arch. The roof of the temporal fossa is formed by this fascia which we have reflected up. This is the temporalis fascia, the deep temporal fascia. The deep temporal fascia is attached to the superior temporal line and as it comes down it splits into two layers as you can see here and these two layers then get attached to the outer and the inner surfaces of the zygomatic arch. This is the outer and this is the inner and it gets attached to the zygomatic arch. This deep temporal fascia provides a strong counter support from top against the downward pull of the masseter on the zygomatic arch. Just to bring you up to speed and this deep temporal fascia, the true temporalis fascia should not be confused with this, this is the superficial temporal fascia also called the temporal gratin fascia, which is the lateral extension of the galliarponeurotica and which contains the superficial temporal vessels. So, these are actually outside the temporal fossa, we should not confuse it with them. So, that brings me to the contents of the temporal fossa. Once we reflect this we can see the most important content of the temporal fossa and that is this muscle here. This is the temporalis muscle and the other content are the deep temporal vessels, one of which we have retained here. The deep temporal vessel is a branch from the maxillary archery. Let us talk about this temporalis muscle. We can see the full extent of the temporalis muscle here. It goes all the way. It is attached to this inferior temporal line. Therefore, it has got vertical fibers and it has got horizontal and oblique fibers. Vertical fibers are anterior and the horizontal oblique fibers are posterior. All the fibers then converge in a fan shaped fashion. They go under the zygomatic arch and my finger is going under the zygomatic arch and they get inserted onto the coronoid process of the mandible and the temporal crest of the mandible here. So, the fibers are going like this and they get inserted. So, therefore, when the anterior vertical fibers they contract, they elevate the mandible and when the posterior oblique fibers they contract, they redrew the mandible. So, that is the action of the temporalis muscle. It also helps in lateral movement of the jaw. Its lateral temporalis muscle helps in lateral movement of the jaw, but that is a minor action. The clinical correlation pertaining to the temporal region is injury to the lateral surface of the skull, which can fracture the tereon and can rupture the middle benignal archery, which runs right under the tereon and lead to extradural hematoma, which can be life threatening. In such situations, it is necessary to do what is known as a burr hole and so here one of my assistants is going to do the burr hole. So, let's take a look at the landmark that we can use. So, this is the zygomatic arch. We take the midpoint of the zygomatic arch and we go approximately one and a half inches above that, where my finger is pointing. So, this is the approximate location of the tereon and this is the place where we will split open the temporalis muscle and my assistant is going to split open the temporalis muscle. Good. That is the region of the tereon. So, once we have split open the temporalis muscle and then we open it, this region that we see here, this is the region of the tereon and here we make a burr hole and we evacuate the hematoma and like it the middle benignal archery. So, this is the principle of evacuating a middle benignal archery hematoma. Okay. Thank you ladies and gentlemen. This is a video on a demonstration on how to evacuate an actual dural hematoma through the middle benignal archery. If you have any questions, put it in comment section. Dr. Sajey Sanyal signing out. Now, let me mention something about the next muscle that we can see here. This is the masseter muscle. As I mentioned, it is one of the strongest muscles of mastication. It is attached to the zygomatic arch here and we have cut it at the attachment of the zygomatic arch and we have removed it. It is also attached partially to the lateral surface of the ramus of the mandible. This is the ramus of the mandible and it gets inserted onto the lateral surface of the angle of the mandible on the masseter tuberosity. Masseter muscle is a strong muscle and it has got two sets of fibers. These are the deep fibers and these are the superficial fibers and we can see them clearly here. Deep fibers are responsible for elevation of the mandible. So, therefore, it is a powerful closure of the mandible. The superficial fibers are responsible for protrusion of the mandible. So, that is the action of the masseter muscle. The masseter muscle when it exerts a strong downward pull on the zygomatic arch, it is countered by the deep temporal fascia which is attached to the zygomatic arch from above. The structures which are in relation to the masseter muscle, we can see the structure here. This is the parotid duct of the stensin duct. Incidentally, this patient has got an accessory parotid gland here and this is just in front of the main parotid and this is called a sosia parotidis. This is one structure which runs on the surface of the masseter muscle, that is the parotid duct and then it pierces the buccanator. The second structure which is in relation to the masseter muscle is this artery here. This is the facial artery and this runs above the lower border of the body of the mandible and we can feel its pulsation against the body of the mandible just in front of the masseter muscle. This is another important relationship that we can see here. Once we remove the masseter muscle, now we are very close to the intratemporal fascia. The intratemporal fascia is deep to this ramus of the mandible. So therefore, if we want to approach the intratemporal fascia, we have to cut four structures. One, we will have to cut the zygomatic arch. Two, we have to cut the coronoid process of the mandible. Three, we will have to cut the condyle of the mandible at the neck. And four, we will have to cut the ramus of the mandible at the angle and then once we remove this piece, then my instrument has gone into the intratemporal fascia. So, that brings me to what are the structures which we can see arising from here once we have reflected both the parotid gland as well as the masseter. We can see first of all this nerve, this is the facial nerve. Let us trace the facial nerve from outside. We can see the facial nerve is supplying some of the muscles of facial expression. And as we trace the facial nerve further deep inside, we notice that the facial nerve is coming out here and it is breaking up into a plexus. This plexus was inside the parotid gland which we have removed. So, this is the facial nerve. And we can see that the facial nerve is winding around the neck of the mandible, lateral to the neck of the mandible as it emerges from the stylo master for a minute. So, therefore, any surgery of the parotid gland or any fracture of the neck of the mandible is likely to jeopardize the facial nerve. The next structure that we can see is this artery here. This is the deep auricular artery. The deep auricular artery is the first branch from the first part of the maxillary artery. It supplies the temporal mandibular joint, it supplies the external arteries and it supplies the tippinic membrane from outside. The next structure that we can see is this artery here. This is the superficial temporal artery. The superficial temporal artery is the smaller terminal division of the external parotid artery. The larger terminal division is the maxillary artery which we cannot see because it goes into the infrared temporal fossa. The superficial temporal artery is also torches and it runs on the superficial temporal fascia and we can see it running here. This is the proximal portion of it. This is the distal portion of it. And as it runs in front of the tragus of the ear, we can feel the pulsation of the superficial temporal artery against the zygomatic artery. So, this is used clinically to evaluate this superficial temporal artery. The next structure that we can see here is this. This is the superficial temporal vein. This is formed from the scalp by union of frontal and parietal veins and it descends down and inside the parotid gland which we have removed here, it receives the maxillary vein. We can see it here and then it becomes known as the retro mandibular vein. Ideally the retro mandibular vein is supposed to divide into an anterior and a posterior division. And the posterior division is supposed to unite with the posterior auricular vein, but in this case the retro mandibular vein itself is meeting with the posterior auricular vein and it is considering down as the retro mandibular vein. And the retro mandibular vein here is dividing into an anterior division and a posterior division. And this posterior division continues as the external zycular vein, while the anterior division meets with the facial vein to form the common facial vein, which will open into the internal jugular vein and this by the way is a communication with the anterior jugular vein which we shall see in the neck. That is the another structure that we can see here. We can see after we have removed the superficial part of the parotid gland we can see the deep part of the parotid gland here. The deep part is narrow and wedge shape and it is in relation to the styloid process. So these are all the structures that we can see here in the region of the muscles of mastication and the parotid. Thank you very much for watching. If you have any questions or comments please put them in the comment section below. Dr. Sanjay Sanyal signing out have a nice day. Please like it sir.