 So, this is going to be a demonstration of the parotid gland in the parotid region. This is the left side parotid gland that we have dissected out. It was covered by a tight parotid sheath which is derived from this investing layer of deep cervical fascia and that is referred to as the parotid mesatric sheath also because it is continuous with the sheath covering the mesater muscle. So, we have completely dissected it out and separated it out. This is the parotid gland. Let's take a quick look at the bed of the parotid. This is the bed of the parotid and the bed of the parotid is formed by the ramus of the mandible. The muscles attached to the ramus of the mandible namely the mesater on the outside and the medial teregoid on the inside that is one part of the bed. Other part of the bed is deep inside which you cannot see and that is the styloid process and posteriorly we have the bastard process posterior superiorly here where my finger is located. This is the location of the external artery meters and superiorly this boundary is formed by the zygomatic arch. So this is the extent of the parotid. The parotid gland is divided into a superficial part which you can see here which is flat and a deep portion which is more wedge shaped and that is the one which attaches itself to the styloid process and to the stylo mandible or ligament which incidentally is also derived from the interesting layer of deep cervical fascia. The parotid gland is also related to the upper part of the sternocleomastoid with which it was fused and we have separated it out. This is the sternocleomastoid on the left side. Now having mentioned the parotid gland now let me just quickly show you the duct of the parotid. This is the stensin start. We can see it is arising from the anterior border of the parotid gland from the superficial part of the parotid gland and it runs on the surface of the mesetra muscle and then it goes and it pierces through this muscle here that we can see and this is the vaccinator muscle and it opens opposite the crown of the upper second molar tooth. In some patients like in this cadaver we can see some accessory parotid tissue. This is referred to as sosia parotidis. The opening of the stensin duct is used for cannulation in the radiographic procedure called xylography to determine if there are any stones or strictures to the parotid duct. This is the parotid xylogram to show an irregular stensin duct and it is branching inside the parotid gland. Now let us show the structures which are located inside the parotid gland. I will draw your attention to these neuromestral structures here on the temporal region. We can see this vein here. This is the superficial temporal vein. It is running on the temporal region and this is the superficial temporal artery. This is tortuous. The superficial temporal artery position can be felt in front of the tragus of the ear against the zygomatic arch and it is used by anesthetists because these are going to be relevant to the structures which are located inside the parotid. So for that we will reflect the parotid and in so doing let me draw your attention to this first structure here. This is the retro mandibular vein. This is called the retro mandibular vein because it is located behind the ramus of the mandible, the normal anatomical position. We have reflected it and we can see it is receiving this vein here. This is the posterior auricular 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 to form the external jugular vein but here we do not see that and the anterior division is supposed to unite with the facial vein to form the common facial vein that also we cannot see clearly here. We can see only the retro mandibular vein and the posterior auricular vein. How does this retro mandibular vein form? Let's go upwards, let's trace it in the reverse direction. We see that this is the superficial temporal vein which I have lifted up here. This is the superficial temporal vein. The superficial temporal vein it receives the middle temporal vein it also receives frontal and parietal branches and as it continues down inside the parotid gland it receives a vein from inside the infrared temporal fossa which we cannot see clearly here. That vein is referred to as the maxillary vein. It's not a very big vein it's quite a small one and it is definitely not the counterpart of the maxillary artery. This maxillary vein unites with the superficial temporal vein and after that it becomes known as the retro mandibular vein and I have already mentioned further termination of the retro mandibular vein. So this is one important structure which is located inside the parotid. Medial to the retro mandibular vein we can see this structure here. This is the external parotid artery. The external parotid artery comes up it goes under the posterior digastric. It divides into its two terminal divisions. The largest terminal division we cannot see because it goes inside the infrared temporal fossa but it is here where my instrument is located and the smaller terminal division is this one here which I have lifted up. This is the superficial temporal artery. This is the smaller terminal division of the external parotid artery and you can see it is running in front of the tragus of the ear and this is where we can feel its pulsation against the zygomatic arch and this superficial temporal artery has got same distribution as the tributaries of the superficial temporal vein namely it has got frontal and parietal branches which supplies the skin of the scalp. This artery is used as a vasculitis pedicle in temporal osteoplastic craniotomy. The third structure which is of note inside the parotid gland is this one and for that we are going to go in the opposite direction. I have lifted the parotid gland and we can see this nerve here and I have lifted it up here. This is the facial nerve. Facial nerve comes out from the stylo-mastered forearm. This is the lateral bone structure. It is situated lateral to the retromandibular vein. It gives a posterior auricular branch. It gives a branch to the posterior belly of the gastric and the stylohyde muscle and after that it enters into the parotid and we can see that entering into the parotid. We have split the parotid to show the branches. First it divides into two principal divisions. This upper one is referred to as the temporal facial division and the lower one is referred to as the cervical facial division and we can see from the divisions multiple branches are coming out and this is referred to as the best and sereneness of the facial nerve. The temporal facial division gives this branch here which you can see. This is the temporal branch. The second branch is this one. This is the zygomatic branch and these supply the muscles on the upper part of the face of the scalp especially the frontalis muscle. The cervical facial division gives rise to this branch here. This is the buccal branch. Then it gives rise to a marginal mandibular branch and further down it will give rise to the cervical branch which supplies the prettiest muscle. So this is the facial nerve that we can see here with its two terminal divisions and its multiple branches including the best and sereneness inside the parotid gland. That brings me to the next clinically important point. Parotid surgery is the most common cause of injury to the facial nerve and therefore to prevent injury to the facial nerve we use a surgical plane referred to as the fasiovenous plane of PT. That fasiovenous plane of PT is actually a combined plane created by this facial nerve and the retromandibular vein. So if we pick up the retromandibular vein and we lift it up like this we pull the facial nerve out of the way that divides the gland into a superficial portion and a deep portion and enables us to do what is known as superficial parotidectomy with less chances of injury to the facial nerve. However again to repeat facial nerve injury is most commonly produced by parotid surgery. These are some of the points which I want to tell you about the parotid gland and its relations and its clinical correlations. Thank you very much for watching Dr. Sanjay Sanayal Sanyamth. Davey knows the camera person. If you have any questions or comments please put them in the comment section below. Have a nice day.