Circumorbital and Palpebral Group – Facial Muscles

00:01 The next muscle here is a sphincter.

00:04 Essentially, it's a sphincter of the eye and this is the orbicularis oculi.

00:10 And here you see the para musculature associated with each eye.

00:15 The orbicularis oculi is going to originate from the medial margin of the orbit.

00:23 And this would be the orbital part of the orbicularis oculi.

00:29 It also then will have an origin for the medial palpebral membrane and this will be the palpebral portion of the orbicularis oculi.

00:39 And then it has an attachment to the thin lacrimal bone as well.

00:47 Insertion of the muscle is the skin and the orbit.

00:52 It also has attachment or insertion points to the tarsal plates that are associated with the upper and lower eyelids.

01:00 So you have superior tarsal plates, as well as inferior tarsal plates.

01:05 Again, innervated by the facial nerve, and specifically the temporal and the zygomatic branches.

01:12 Temporal branches would innervate the superior portion of the orbicularis oculi.

01:18 Whereas, the zygomatic branches are going to innervate the inferior portion of the muscle and because it's a sphincter, it will then close the eyelids.

01:29 And this allows one to wink or squint, particularly, if you're looking into bright sunlight.

01:39 Next, is this very hard to kind of see here but it is highlighted in red.

01:45 This particular muscle that is paired is the corrugator supercilii.

01:51 It's gonna have origin from the medial end of the supercillary arch, which is a bony eminence of the frontal bone.

01:59 And its insertion will be due the skin of the supercillary arch as well of the skin that overlays the supraorbital margin.

02:10 Again, innervated by the facial nerve and specifically it will be the temporal branches of the facial nerve providing that innervation.

02:18 When the muscle contracts it will pull the eyebrow inferiorly, as well as medially, and it'll also produce wrinkling of the skin above the nose.

02:31 These vertical wrinkles that result from contraction of this muscle help to demonstrate a concern or a worry type of appearance.