 A demonstration of the muscles of facial expression, this muscle which we have picked up here, this is the frontalis muscle. And we can see it is taking origin from the glia aponeurotica and then the fibers come down and they merge with the fibers of the orbicularis oculi and they get inserted onto the subcutaneous tissue of the forehead. This is responsible for piercing horizontal wrinkles on the forehead. Action of the frontalis is enhanced by the action of occipitalis which is not visible here. When the occipitalis contracts, it makes the glia aponeurotica tight and then it increases the functionality of the frontalis muscle. The next muscle that we can see here is these muscle fibers and we have to see very carefully. This is the procedures. The procedures is responsible for producing horizontal wrinkles on the root of the nose, something like a sneering expression. Further laterally, we cannot see it here, muscles will be coming from the lateral aspect and going like this. That is known as the corrugator super-silite which is responsible for producing the frowning expression where it produces vertical creases on the forehead. The next muscle is the levator labiae superioris alec nasi and the ailer part of nasalis. The muscle that we see here, this is the levator labiae superioris. This is responsible for elevating the upper lip. After that, we can see another group of muscles here. This is the levator angolae aureus. When both the sides, levator angolae aureus work, they again elevate the angles of the mouth and therefore they produce a smiling expression. One side, when it works, it again produces a sneering expression. The next muscle that we can see here is this one, arising from the zygomatic bone and going. This is known as the zygomaticus major and there will be a smaller muscle media to that which is the zygomaticus minor. This also bilaterally when it works, it elevates the angles of the mouth and therefore bilateral zygomaticus major and bilateral levator angolae aureus are responsible for producing a smiling expression. The next muscle that we can see here, these muscle fibers. These are the depressor angolae aureus and deep to this, we have risorius and the depressor labiae inferioris and further closer to the midline, not dissected out here will be the mentalis muscle. If you go further down, we can see these muscle fibers under the skin of the neck and we can see some of the muscle fibers are attached to the under surface of the skin also. This is the platysma. The platysma makes the skin of the neck tight, like for example when we are shaving or it can also help to depress the mandible against resistance. Now let's come further up again here. We have this muscle here, where my instrument is pointing inside. This is the buccinator muscle. The buccinator muscle takes origin from the alveolar process of the maxilla mandible and it also takes origin from a fibro structure posteriorly known as the terego mandibular raffle. And anteriorly, it merges with the structure called the modulus, which I should describe just now and it also merges with the fibres of the auricularis oris. The buccinator is known as the trumpeter's muscle. When a person is blowing a trumpet, he balloons his cheek out and that is done by the buccinator. The buccinator also acts as an accessory muscle of restication. When the person is chewing, the buccinator holds the food between the upper and the lower teeth. That brings me to the concept of modulus. The modulus is a fibromuscular condensation. It's shaped like a cartwheel, which is situated approximately 1 centimeter or 10 millimeters lateral to the angle of the mouth in this region. The modulus gives attachment to eight muscles, three from the top, three from below, one from posterior laterally and one from medially. The three muscles from the top are, and we can see some of them, zygomaticus major, libator labiaeus superioris and libator anguli auris. Correspondingly, the three muscles from below are depressor anguli auris, isorius and depressor labiaeus inferioris. Laterally, we have this muscle, which I've already mentioned, the buccinator. And from the medial side, we have the fibromuscularis auris. And we can see a few of the fibres of the auricularis auris here, but most of them are around the upper and the lower lip. So these eight muscles, they converge in the region of the modulus. When there's a facial pass, see this modulus drops down and that is what produces drooping of the angle of the mouth. Coming back to the buccinator, we notice this structure piercing the buccinator. This is the parotid duct or the stensis duct. And this pierces the buccinator after running on the surface of the masseter muscle. And it opens opposite the crown of the upper second molar tooth. This cavity that you can see here, this was filled with the buccal pad of fat. This is the one which gives the chavi-cheek appearance in children. The fat extends even under the zygomatic arch to the temporal fossil. All the muscles of facial expression, they are derived from the second brachial arch. Therefore, they're all supplied by branches of the facial nerve. And we can see the facial nerve under the parotid here. This is the facial nerve that we can see here. So these are the muscles that I wanted to demonstrate to you. 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. Anderson is the camera person. Have a nice day.