I'm Dr. Gonzalez and today in this video we're talking about the following topics. In the muscles of facial expression, basically almost all of your muscles of facial expression are innervated by the cranial nerve number 7, the facial nerve. This facial nerve has several branches including a temporal branch, branch, zygomatic, buccal, marginal and the cervical branch.
So the first muscle is the one indicated here in red and blue, particularly red is the most is the area where the muscle fibers are located. Blue is the aponeurosis. So this muscle is called the occipitofrontalis. Other books also call it the epicranius. It has two bellies, a frontal belly and an occipital belly.
In this view, you're looking at the frontal belly. This muscle has an origin at the epicranial aponeurosis and an insertion in the skin and subcutaneous tissue of the eyebrows and forehead. And the action is to elevate the eyebrows and wrinkles the skin of the forehead, particularly whenever a person is surprised.
Second muscle is the orbicularis oculi which is this one you can see right here. The origin is on the medial orbital margin, medial parpibral ligament and the lacrimal bone. The insertion is in the skin around the margin of the orbit or the eyelid in other words and the action is to close the eyelids particularly the palpebral part which is the lower portion is there to close very gently the eye meanwhile the orbital part which is the superior portion it closes the eyelids tightly and it also works during winking The third muscle is the corrugator superciliae which is this muscle that's right here.
In this muscle the origin is at the medial end of the superciliary arch. The insertion is the skin superior to the middle of superorbital margin and the superciliary arch and the main action is to draw eyebrows medially and inferiorly creating vertical wrinkles above the nose. demonstrating concern or worry and also when the person is in a very much the fourth and fifth muscle here is the process is this muscle right here and the transverse part of the nasalis.
The nasalis is this muscle right here. So the origin is going to be the fascia aponeurosis that's covering the nasal bone and lateral nasal cartilage. The insertion is going to be the skin of the inferior forehead between the eyebrows.
And the main action is to depress the medial end of the eyebrow. And it also wrinkles the skin over the dorsum of the nose like when you are conveying something that you dislike Number five is the other part of the nostalis Right here And the Levator Labi Superioris Aleque Nasi, which is this one right here. So the origin of these muscles is on the frontal process of the maxilla, inferior medial margin of the orbit, and the insertion is the major alar cartilage and the action is to depress or depress the alar laterally, dilating the anterior nasal aperture such as in flaring the nostrils during anger.
This muscle right here is also known as the oral sphincter and the origin is the medial maxilla and mandible, deep surface of the preoral skin and angle of the mouth. The insertion is the mucous membrane of the lips and the action is to tone the closest, tone closest of oral feature. It also has a contraction and it compresses or protrudes the lips such as in kissing or resists the distension when blowing. Number seven is these two muscles. Levator labii superioris, which is this one right here, and the zygomaticus minor, which is this one right here.
For the levator labii superioris, the origin is the infraorbital margin, or the maxilla. And for the zygomaticus minor, the origin is the anterior aspect of the zygomaticus. In terms of the insertion, both of these muscles they insert in the skin of the upper lip and the action for these muscles is to, they are part of dilators of the mouth.
They will retract or elevate and or avert the upper lip and they will deepen the nasolabial sulcus as in showing sadness. The origin for the zygomaticus minor is muscle number eight is the boxinator which is a cheek muscle. The origin is the mandible alveolar processes of the maxilla and mandible and the pterygomandibular raffae. The insertion is the angle of the mouth and the orbicularis poris and the action is to press the cheek against the molar teeth.
It also works with the tongue to keep the foot between the occlusal surfaces and out of the oral vestibule and it also resists distension such as when blowing. Next is the zygomaticus major. The zygomaticus major is this muscle right here.
And the origin is the lateral aspect of the zygomatic bone. The insertion is the angle of the mouth. And the action is part of dilators of the mouth.
It elevates the labial commissure. And it bilaterally affects the elevation of the labial commissure, like when you're smiling or in happiness. and unilaterally to sneer.
Next is the levator anguliores, which is this muscle right here, deep to the zygomaticus. The origin is the infraorbital maxilla. The insertion is the angle of the mouth.
And the action... Part of dilators of the mouth, it widens the oral fissure as when grinding. Rhistorius is this muscle right here and the Depressor anguli oris. is this one right here these two muscles they have an origin on the parotid fascia and both skin this is mostly the risorius and the pressor anguli oris has an origin and the anterior lateral base of the mandible.
Both of these muscles have an insertion in the angle of the mouth and both of these muscles are part of dilators of the mouth. They depress the labial commissure bilaterally to frown during sadness and also the restorers can draw the corner of the lip naturally. Next is the Depressor Labi Inferioris.
The Depressor Labi Inferioris is this one right here. The Depressor Labi Inferioris has an origin in the platysma and a pterolateral body of the mandible. It has an insertion in the skin of the lower lip.
And in terms of action, the Depressor Labi Inferioris is a part of the dilators of the mouth. It retracts or depresses the mouth. or it works the lower lip as in powder or sadness the mentalis is this muscle right here and the origin is the body of the mandible the insertion is the skin of the shin and the main action is to elevate and protrude the lower lip and it also elevates the skin of the shin like showing doubt Last but not least is the platysma which is this muscle right here.
The origin of the platysma is the subcutaneous tissue of the infraclavicular and supraclavicular regions. The insertion of the platysma is the base of the mandible, skin of the cheek and lower lip and angle of the mouth, particularly on the orbicularis oris. And the action.
is to depress the mandible against resistance. It tenses the skin of the inferior face and neck, conveying tension and stress. Alright, that is it for this video.
Thank you for watching. Don't forget to subscribe, like, and share. And if you have any comments or suggestions, you can leave them on the comments section.
Also, don't forget to check out my Etsy store, Queen Mary Anatomy. That is it. I'll see you next time.