humans make many different facial expressions and they are an extremely important way that we communicate they let people know when you happy like after getting a good Mark on an anatomy test or curious like when you learn something new about the human body let's learn about the muscles responsible for our facial expressions first let's start with the scalp which is a layer of skin and subcutaneous tissue that covers the cranium it extends from the supraorbital margins on the frontal bone to the superior nucal line on the occipital bone laterally it covers the temporal fascia and extends to the zygomatic arches on each side the scalp is made of five layers which can be remembered easily as the first letter of each spells out the word scalp going in the order from superficial to deep s stands for skin C stands for connective tissue a stands for aerosis or epicranial aerosis L stands for loose connective tissue and P stands for parac Cranium which is the periostium on the external surface of the cranium the first three layers skin connective tissue and the aerosis are connected tightly together forming a single unit called the scalp proper muscles of facial expression simply known as the facial muscles are found deep in the skin of the scalp face and neck most facial muscles are attached to bones or fascia on one end and skin on the other so that when they contract they create facial expressions all facial muscles originate from the mesoderm of the second Fingal Arch along with the facial nerve during embryological development a muscular sheet forms and begins to spread over the scalp face and neck which later forms the facial muscles this spreading carries the branches of the nerve of the second arch with it which is the facial nerve or cranial nerve 7 so so all facial muscles are inated by the branches of the facial nerve which are the posterior aric temporal zygomatic Buckle marginal mandibular and cervical nerves a way to remember these last five branches that emerge from the paraded gland is by using the pneumonic to Zanzibar by Motorcar now let's look at each of the facial muscles first up the occipital frontalis muscle which has two bellies the two bellies are connected by the epicranial aerosis which is the aerosis that makes the third layer of the scalp the frontal belly originates on the epicranial aerosis and inserts on the skin superior to the eyes and nose it is innervated by the tempor nerve the occipital belly originates on the superior nucle line of the occipital bone and inserts on the epicranial aerosis the occipital belly is inated by the posterior oric nerve now when the frontal belly contracts it protracts the scalp and when the occipital belly contracts it draws the scalp back when they work together they elevate the eyebrows and wrinkle the forehead making you look surprised next up is the orbicularis oculi muscle which has two main parts the palpal part and the orbital part the palpal part is found mostly within the eyelid and it originates on the medial palpal ligament and inserts on the lateral palpebral ligament the orbital part originates from the medial orbital margin and medial palpal ligament and inserts on the skin around the orbit forming a continuous ring that surrounds the orbital orifice the Superior part of the orbicularis oculi muscle is interated by the temporal nerve while the zygomatic nerve innervates the inferior part of the muscle the function of the orbicularis oculi muscle is to close the eyelids the palpal part closes the eyelids gently like when you blink or sleep while the orbital part closes the eyelids tightly like when you wink or squeeze the eyes shut okay let's move on to the muscles of the eyebrows and the nose the muscle of the eyebrows is called the corrugator super cyi which sounds like a spell you'd learn at Hogwarts but is actually a small muscle found deep in the eyebrows and is innervated by the temporal nerve corrugator supercilii originates on the medial part of the superciliary arch and extends laterally to insert onto the skin of the medial half of the eyebrow when it contracts the corrugator supercilii pulls the eyebrows medially and inferiorly making vertical wrinkles at the root of the nose which occurs when frowning now let's move on to the nose there are three muscles of the nose the procerus nasalis and the levator labii superioris alqua Nai all three muscles of the nose are innervated by the zygomatic nerve the procerus originates on the nasal bone and the lateral nasal cartilage and inserts onto the skin in the lower part of the forehead between the eyebrows when it contracts it depresses the medial ends of the eyebrows and creates transverse wrinkles on the dorsum of the nose the largest muscle of the nose is the nasalis which is made of two parts a transverse part and an AER part the transverse part originates on the maxilla on either side of the nose and extends towards the dorsum of the nose meeting in the midline to insert on an aerosis the AER part also originates on the maxela over the lateral inzer and inserts on the AER cartilage the transverse part Narrows the nostrils and the AER part expands or flares them the levator labii superioris alqui originates on the the frontal process of the maxilla and inserts on the upper lip and the AER cartilage of the nose it flares the nostrils and raises the upper lip okay now let's take a short break and try to remember which facial muscle closes the eyelids right it's the orbicularis oculi muscle now let's tackle some muscles in the oral region first up is the orbicularis orus muscle which encircles the mouth it originates on the maxilla the mandible and on the angle of the mouth called the medis all of the fibers insert on the mucus membrane of the lips the orbicularis orus muscle is innervated by the Buckle nerve and its function is to close the mouth by bringing the lipss together and protrude the lips like when kissing or whistling so next time you are whistling a Happy tune remember it's the orbicularis orus that does the work as for the muscles of the lips we'll divide them into the muscles of the upper lip and the muscles of the lower lip the muscles of the upper lip are the rosorius the levator anguli Ora the zygomaticus major the zygomaticus minor the levator labii superioris and the levator labii superioris elake Nai which we mentioned earlier the rosorius originates on the paraded fascia and the Buckle skin and it inserts on the medis the rosorius retracts the corner of the mouth the levator anguli orus originates on the infraorbital maxilla and also inserts on the medis it raises the corner of the mouth like when grinning the zygomaticus major originates on the zygomatic bone and inserts on the medis it elevates the corner of the mouth so we can smile the zygomaticus minor originates on the zygomatic bone and inserts into the skin of the upper lip the levator Lei superioris originates on the infraorbital margin of the maxela and also inserts into the skin of the upper lip the zygomaticus minor levator labii superioris and the levator Lei superioris elqui pull the upper lip upward of course all muscles of the upper lip are also dilators of the mouth and they're all innervated by the zygomatic and buckle nerves now the muscles of the lower lip are the depressor anguli orus and the depressor labii inferioris the depressor anguli orus originates on the base of the mandible and inserts on the medis it pulls the corner of the mouth downwards to express sadness the depressor labii inferioris originates on the anterolateral body of the mandible and the platisa muscle it inserts into the skin of the lower lip it pulls the lower lip downward when you are sad or when you pout just like the muscles of the upper lip both muscles of the lower lip are also dilators of the mouth the marginal mandibular nerve innervates both the depressor anguli orus and the oppressor labii inferioris okay now let's discuss a muscle of the chin called mentalis the mentalis originates on the body of the mandible and inserts into the skin of the chin it elevates and protrudes the lower lip like when pouting and is innervated by the marginal mandibular nerve lastly we have a broad muscle of the neck NE called plma it originates on the suprascapular and the infraclavicular subcutaneous tissue the platisa extends towards the Mand and inserts on the base of the Mand blending with the facial muscles the platismatia neck to express stress since that was quite a bit of information we can take a break here now can you name all the muscles of the upper lip in this image before we wrap up let's look at one final facial muscle called the buxin nator the buxin nator is a rectangular muscle found deep in the cheek it originates on the alv processes of the max and the mandible and the terago mandibular Ry now the terago mandibular Ry or the terago mandibular ligament is a thickening of the Buckle fenal fascia the superior fenal constrictor originates on the posterior side of the terago mandibular Rafi while the binat originates on the anterior side the buxin nator extends anteriorly where its fiber mingle with the fibers of the orbicularis orus muscle and inserts on the medis the buxin nator is innervated by the Buckle nerve and its main job is to press the cheek against the teeth like when you're drinking from a straw all right as a quick recap the scalp is a layer of skin and subcutaneous tissue that covers the cranium it is made of five layers skin connective tissue aerosis loose connective tissue and pericranium all facial muscles originate from the mesoderm of the second fenal Arch which is why they are all innervated by the branches of the facial nerve the occipito frontalis muscle has a frontal belly and an oxital belly which are connected by the epicranial aerosis its function is to elevate the eyebrows and wrinkle the forehead the orbicularis oculi muscle surrounds the orbit its palpal part is found within the eyelid and is used to close the eyelids gently and its orbital part is used to close the eyelids tightly the muscle of the eyebrow is called corrugator supercilii and it draws the eyebrows downward and medially which occurs when frowning the three mus muscles of the nose are the procerus nasalis and the levator Lai superioris alqua Nai the nasalis and the levator Lai superioris alqua Nasi are used to flare the nostrils the orbicularis orus encircles the mouth and its job is to close the mouth or protrude the lips the muscles of the upper lip are the orus the levator anguli orus the zygomaticus major the zygomaticus minor the levator labii superioris and the levator labii superioris Al Nai all muscles are involved in various lip movements muscles of the lower lip are the depressor anguli orus and the depressor labii inferioris both the muscles of the upper and lower lip are dilators of the mouth the mentalis is a muscle of the chin and elevates and protrudes the lower lip the platisa is found in the neck and depresses the mandible draws the corner of the mouth downwards and tenses the skin of the lower face and neck finally the binat is a rectangular muscle found deep in the cheek and presses the cheeks against the teeth helping current and future clinicians Focus learn retain and Thrive learn more