 This is supine cadaver. This is the right side. I'm standing on the right side and the camera person is also on the right side This muscle that we see here This is the posterior biogastric which takes origin from the mastoid process and the intermediate tendon gets attached to the Hyoid bone by means of facial sleep and also just under the posterior biogastric. We have this muscle here This is the style of Hyoid muscle which takes origin from the styloid process and goes almost parallel to the posterior biogastric Then we have this muscle here. This is the anterior belly of digastric Which starts from the intermediate tendon at the Hyoid bone and goes and attaches to the mandible here And the supia boundary of the submandibular triangle is this line The inferior border of the mandible till the angle of the mandible which we have cut here and from there an imaginary line Going to the mastoid process. So therefore this is the submandibular or the digastric triangle This was covered by the platysma and we can see remnant of the platysma here That is the roof. Now, let's come to the floor for that I will reflect this structure and we can see the floor is composed of three different muscles. Immediately we have this muscle here This is the mylohyoid muscle Just after the mylohyoid we have the next muscle for that again. I'm going to reflect this up to show this muscle This is the hyoglossus And further laterally we have the middle pharyngeal constrictor The middle pharyngeal constrictor is located where my instrument is located here This is the region of the middle pharyngeal constrictor. So these are the three structures which constitute the floor Now, let's take a look at the contents. The most obvious content that we can see is this structure here Which is highly enlarged in this particular cadaver. This is the submandibular salivary gland I have reflected the submandibular salivary gland to show the other contents So let's start with first content that we can see here. This is the facial artery on the face So let's trace the origin of the facial artery from the external carotid artery. So this is the external carotid artery and We can see going anteriorly we have three arteries superior thyroid artery Linguel artery facial artery So this is the facial artery The facial artery goes under the posterior digastric and the stylohyde and then it hooks under the body of the mandible And at that place it gives off two branches and we can see the two branches here This is the ascending palletine artery and This is the tonsillar branch which supplies the tonsil then the facial artery comes down and it hooks Under the lower border of the mandible and we can see the rest of the facial artery coming up here And as it goes it grooves a posterior aspect of the submandibular gland And we can see it is grooving the posterior aspect of the submandibular gland So this is the full course of the facial artery that we can see here and I have extended it out and in the face It's following a tortuous course. So this is one content of the submandibular triangle Then we have the next content. This is the shell vein The facial vein comes from below and we can see the rest of the course of the facial vein here The facial vein and facial artery both of them receive multiple branches from the Submental region and this also grows in close proximity with the submandibular Salivary gland and here the facial vein is receiving multiple communications one communication is Coming from the lingual vein, which is located deep inside. It receives this communication Which is the lingual vein it receives the communication from the posterior auricular vein which came from the intratemporal fossa and we have brought it out and Then the facial vein opens into the internal jugular vein by means of these two tributaries this is the main opening Which we have cut and this is the secondary opening into the internal jugular vein. So this is the facial vein So we have seen the facial artery in the facial vein now. Let's take a look at structures below I have reflected the submandibular salivary gland again The next structure is this one which I have lifted up This is the lingual artery. This is the second anterior branch after the superior thyroid artery The third branch was the facial artery, which we have already described the lingual artery as it comes out It makes an upward loop and we can see that loop here and then it goes down and it enters Deep to the hyoglossus and we can see it is disappearing under the hyoglossus muscle The hyoglossus incidentally was one of the structures which forms the floor of the submandibular region And then it supplies the tongue by means of the deep dorsal and the sublingual branches The next structure that we can see is crossing in front of the lingual artery is this nerve This is the hypoglossal nerve The hypoglossal nerve follows this course in front of the bifurcation of the carotids It goes in front of the lingual artery and then it disappears under the tongue deep to the mylohyoid muscle But superficial to the hyoglossus. Here we can notice that hypoglossal nerve is giving these two branches These are not branches from the hypoglossal proper These are branches from the superior limb of ancestral vicalis Which came out from the loop of C1 C2 This is a branch to the thyroid and this is the superior limb of ancestral vicalis or the descending hypoglossi Which is supplying the omohyate muscle. So this is what we see in the hypoglossal nerve The next structure that we can see in the content is once I reflect again The submandibular salivary gland we can see this nerve here to see this nerve We can trace it from the infra temporal fossa This is a branch from the mandibular nerve which I have lifted up in the infra temporal fossa and we can see this nerve traveling This is the lingual nerve The lingual nerve enters the submandibular salivary gland and we can see it is giving a branch to the submandibular gland This is the secretary fibers which came from the corded tympani nerve and we supply the submandibular gland and Then the main lingual nerve then continues into the floor of the mouth deep to the mylohyoid and we can see it disappearing and Accompanying this lingual nerve. We can see this structure here This is the water and stuck or the submandibular salivary duct This is a very important relationship when we are doing a submandibular salivary gland surgery You have to be very careful of the lingual nerve because we may injure the lingual nerve while removing the water and stuck Now that we have restricted the submandibular salivary gland I'm going to draw your attention to one thing we notice that this is the lateral border of the mylohyoid muscle Which I mentioned was the floor one of the floor And this lateral border of the mylohyoid muscle partially splits the submandibular salivary gland into a superficial portion which we can see here and a deep portion which is deep to the mylohyoid and from the deep portion arises this Duct the Warton's duct. So we have seen the lingual artery We have seen the lingual nerve this again to show you this communication is the lingual vein The next structure which I will draw your attention to is in the infratemporal fossa My finger is in the region of the styloid process and from the styloid process We can see three muscles coming out one muscle. I told you in the beginning. This is the cut portion of the stylohyoid muscle This forms one of the boundaries of the submandibular triangle next muscle that we can see here is this muscle This is the stylo-glossus muscle and we can see the stylo-glossus muscle is also entering into the This muscle and above that we can see the third muscle This is the stylo-pharyngeal muscle. Stylo-pharyngeal muscle enters between the superior and the middle pharyngeal constrictor and accompanying the stylo-pharyngeal muscle is this nerve here This is the glossopharyngeal nerve and the glossopharyngeal nerve we can see it is giving one branch to the tongue This is the lingual branch which supplies the posterior one-third of the tongue and then the rest of the glossopharyngeal nerve then enters Into the pharynx with the stylo-pharyngeus and supplies stylo-pharyngeal muscle and it supplies Sensation to the pharynx while we're on the topic of the glossopharyngeal I will draw your attention to two other nerves which also emits through the jugular foramen We can see this nerve here. This is the spinal accessory nerve Which is also coming out through the jugular foramen. This is the next nerve The big one which also comes through the jugular foramen. This is the vegas nerve So these are the three structures which come out through the jugular foramen and since we are talking about the jugular foramen This is the superior bulb of the internal jugular vein The clinical importance of all these things lie in the fact that when we are doing a subbandabula celebrity gland surgery We have to be careful of the facial artery the facial vein the lingual nerve the lingual artery the hypoglossal nerve and there is one more nerve which is not visible here Which runs along the margin of the mandible the lower border and that is known as the marginal mandibular nerve Which is a branch of the facial nerve which also can be injured during Subbandabula celebrity gland surgery that brings me to the next point When do we do a subbandabula celebrity gland surgery? We do it when there's a stone or a stricture in the water's duct and that is diagnosed by a procedure called Silography this is a subbandabula or silo graphing to show stricture in the water's duct on the right side and When we see that then we have to remove the subbandabula celebrity gland if there is any injury to the corded impenny nerve or to the lingual nerve Then there'll be loss of secretion from the celebrity gland and that produces what is known as partial zero-stomia So these are the structures and the clinical correlations that I want to mention in the subbandabula triangle And it's continuity with the infrared temporal fossa and with the neck Thank you very much for watching. Dr. Sanjose and you're signing off. Please like and subscribe if you have any questions or comments Please put them in the comment section below. Have a nice day