hello everyone and welcome back to another anatomy tutorial this is dr ayan from the veterinary anatomy channel in this video we will talk about the muscles of the head of the equine so let's get started okay so let's start with this photo here where we can see most of the muscles of the head especially the one which we can see in the lateral view of the head here of the horse and let's start with the muscles of the lips and cheek and the first one we would like to talk about is the this muscle highlighted in green here is the orbicularis auras or in english we can name it as orbicular muscle of the mouth this muscle look at this animation here close circle around the mouth and the main function of this muscle is to close the mouse opening we have to mention here that this muscle has no attachment to any of the bones of the skull so what is the name of this muscle this is the orbicularis oars muscle the next muscle we would like to talk about is this muscle here highlighted in green the book in eater muscle the buccaneer muscle usually has two parts the molar and buccal parts this muscle originates from two areas as you can see here the first one here is the cranial surface of the coronoid process do you remember this part here this is the coronal head process of the mandible the second origin is the upper jaw at this level here below the facial crest this muscle inserts to the lower jaw at this area here of the mandible and the function of this muscle is to push the food toward the oral cavity so it helps moving the food inside the oral cavity and at the same time don't forget that this muscle forms the lateral wall of the oral cavity the next muscle highlighted in green here is the zygomaticos muscle the zygomaticos muscle originates from the facial crest this is the facial crest here and inserts to the lateral angle of the mouth look at the muscle here or you need from the facial crest and inserts to the lateral angle of the mouse or to the orbicularis auras the function of this muscle is to retract the lateral angle of the mouth and move it backward like this the next muscle highlighted here in green is the canninos muscle canninos muscle originates from the facial crest the cranial border of the or cranial part of the facial crist and inserts two two different areas the first one is the lateral border of the nostril as you can see in this picture here and part of this muscle inserts to the upper lip so from the insertion we can understand the function of this muscle so the function is to elevate elevate the upper lip and widens the nostril opening this is the caninus muscle the next muscle which we can find here is the levator labia superiors muscle or in english the levator muscle of the upper lip this muscle originates from the lacrimal bone this is the lacrimal bone of the skull in the horse so from this area of the lacrimal bone and inserts to the upper lip if you follow the tendon of this muscle uh we will find that the tendon of this muscle from this side meet with that one of the other side and inserts finally to the upper lip so the function of this muscle is to elevate the upper lip again the function of the levator lobby superiors is to elevate the upper lip the next muscle is for the lower lip called the depressor labi inferior muscle or the inferior the the bristol muscle of the lower lip this muscle originates from the cranial border of the mandibular ramus and inserts to the orbicularis oris as you can see here it inserts to the orbicularis aureus muscle the function of this muscle is to depress and retract the lower lip so contraction of this muscle the bresola being for yours depresses and retracts the lower lip now let's move to the other group of muscles the muscles which are there to to act on the eyelids and the nose and we will start with this circular muscle called the orbicularis ocoli or the orbicular muscle of the eye this muscle surrounds and closed circle around perpetral feature and contraction of this muscle will close the pelvic fissure okay i hope it's clear so contraction of this muscle here will close the pelvic fissure so this opening of the eye of course of the eyelids the next muscle is a small muscle extends between the zygomatic process of the frontal bone which is the origin of this muscle and inserts to the medial end of the upper lid to the medial end of the upper lid called the levator anguli oculi medialis or the the medial elevator muscle of the upper lid from the origin and insertion of this muscle we can understand the function of it which is elevate medial part of the upper lead so elevates the medial part of the abar lead so we are talking about the levator anguli okoli medials now the next muscle called the levator nasolabials or in english the nasolabial levator muscle this muscle originates from the frontal bone and from the beginning of the nasal bone so this is the frontal bone and this is the nasal bone so from this area this muscle originates and inserts into two areas the first one is the orbicularis ores muscle as you can see here and the second one is the upper lid lip so in general if you look at this muscle you will find that this muscle will be divided in this area here into two parts the first part or inserts to the orbicularis aureus the second one inserts to the upper lip and so slightly to the lateral wall of the nose in this area here and that's why the function of this muscle is to elevates the upper lip elevates the upper lip and enlarged the nostril opening here we can mention how the caninus muscle moves inside or between the two parts of the levator nasolabialis muscle the next muscle called the malars muscle it's a small muscle extends between the facial crest or let's say the dorsal border of the facial crest and inserts to the lower lid so from the origin and insertion again we can understand that the function of this muscle to pull the lower lid ventrally to pull the lower lid eventually what is the name of this muscle here malars muscle now let's talk about the other muscles which we can see in the lateral view here we can see this very big muscle called the masseter muscle masseter muscle is one of the mastication muscles it has normally in the horse two parts the superficial and the deep part of the masseter muscle this muscle originates from the zygomatic arch and from the facial crest so from the zygomatic arch and from the facial crest this is the zygomatic arch here if you remember in another video we talked about it and we see that it forms by two processes the first process from the timbral bone called that the zygomatic process of the temporal bone and the second one is the temporal process of the zygomatic bone both of them meet together to form the zygomatic arch so the masseter muscle originates from the zygomatic arch and from the facial crest here and inserts to a very big area here called mesiteric fossa messiter fossa is a depression on the lateral surface of the mandible so from the origin again and insertion of this muscle we can understand the function of it the function of the meseta muscle is to elevate the mandible and presses it again against the maxilla so contraction of this muscle will move the mandible toward the maxilla toward the maxilla and so it helps with mastications the last muscle which we can see here is the mild ohio idios muscle the milo hyoidios muscle originates from the myelohyoid line it's a line on the medial surface of the mandible on each part of the mandible so this muscle extend from the media surface of this part of the mandible to the other surface so it forms the ventral cover of the oral cavity somehow this muscle inserts to the base hyoid and lingual process which is present in the horse base hyoid and lingual process the function of this muscle is to elevate floor of mouth and presses the tongue against the heart palate this is the function of the myelohydios muscle so we talked about most of the muscles which we can see in the lateral view of the head of the horse of course there are some other muscles located more deeply especially at the medial surface of the mandible like for example we talked about the messita muscle as one of the mastication muscles but we know that there are some other mastication muscles like for example the temporal muscle which is lukita or originated from the temporal fossa and this area and inserts to the coronal heat process of the mandible and has the same function like the message muscle so move the mandible toward the maxilla and it's one of the mastication muscles there are some other mastications muscles located medial to the mandible the bacterial e the lateral artery then medial purely muscles but we cannot see them in this view so in another video we will cut the mandible completely and talk about these muscles so if you have any question don't forget to write your question in the comments and share the information with your colleagues 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