 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 the deep cervical fascia and that is referred to as the parotid mesatric sheath also because it is continuous with the sheath covering the meset or muscle. So we have completely dissected out and separated 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 meset or the outside and the medial teregoid on the inside. That is one part of the bed. The other part of the bed is deep inside which you cannot see 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 odrymiatus and superiorly this boundary is formed by the zygomatic arch. So this is the extent of the parotid. This is the skeleton of the skull to show the bed of the parotid gland. So here anteriorly we can see this is the ramus of the mandible. This is the anterior boundary of the bed. This is the mastoid process. This is the posterior boundary. Deep inside we can see the styloid process. Posterior superiorly we can see the external odrymiatus covered by the tympanic plate of temporal bone and superiorly we can see the zygomatic arch. So therefore this area this region constitutes the bed of the parotid and the boundaries of the bed 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-mandibular ligament which incidentally is also derived from the investing layer of team 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. So this is the sternocleomastoid on the left side. So having mentioned the parotid gland now let me just quickly show you the duct of the parotid. This is the stensis duct. 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 masseter 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 stensis duct is used for cannulation in the radiographic procedure called stylo-graphy to determine if there are any stones or strictures to the parotid duct. This is the next way to show a parotid stylogram where the dye has been injected through the stensis duct. The stensis duct itself is visible. Now let us show the structures which are located inside the parotid gland. I will draw your attention to these neuromuscular 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. Superior temporal artery position can be fed 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 retromandibular vein. It is called the retromandibular 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 retromandibular vein is supposed to divide into an anterior and posterior division and the posterior division is supposed to unite with the posterior auricular vein to form the external juggler 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 retromandibular vein and the posterior auricular vein. How is this retromandibular vein formed? Let us go upwards. Let us 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 is not a very big vein. It is 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 retromandibular vein and I have already mentioned further termination of the retromandibular vein. This is one important structure which is located inside the parotid. Media to the retromandibular vein we can see this structure here. This is the external parotid artery. The external parotid artery comes up. It goes under the posterior belly of the gastric. It divides into its two terminal divisions. The larger 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 triggers of the ear and this is where we can feel its position 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 scan. This artery is used as a pedicle vascularized 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 reflected 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 mastoid forearm. It is the lateral mode 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 pletiosma 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 clinical 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. These are some of the points which I want to tell you about the parotid gland and its relations and its clinical correlations.