![]() vascular) layer of the eyeball houses the blood vessels of the eye. The anterior one sixth of the eyeball is covered by the transparent avascular cornea instead. In addition, it acts as an attachment site for extrinsic and intrinsic muscles of the eye. The sclera is the tough opaque wall component of the outer layer covering the posterior five sixths of the eyeball. fibrous) layer gives the eyeball its shape and provides resistance. Let us have a closer look at the individual layers of the eyeball and their components. The wall of the eyeball has three layers: an outer (fibrous) layer, a middle (vascular) layer and inner layer. It has the same function as a digital lens, but in the eyeballs it helps in focusing the light onto the retina. You have probably noticed that there is something in the eye called ‘the lens’, which is also present inside our digital cameras. Posterior to the cornea are the anterior chamber, lens, vitreous chamber and the retina. The most superficial layer of the convexity is the cornea, which refracts and focuses the details of the image. It is round with an anteriorly convex bulge. ![]() It is something like a little camera inside our head, with all the necessary parts for capturing an image. Its importance reflects on its size, making it the largest structure in the orbit. The eyeball is the main structure within the orbit because it enables us to see. Insertion - anterior surface of tarsus, skin of upper eyelidĭon’t understand how all these muscles work? You can find out everything about them in the following learning materials. Insertion - inferolateral aspect of eyeball (deep to lateral rectus muscle)įunction - elevation, abduction, external rotation of eyeball Insertion - superolateral aspect of eyeball (deep to rectus superior, via trochlea orbitae)įunction - depression, abduction, internal rotation of eyeball Insertion - anterior half of eyeball laterally Origin - lateral part of common tendinous ring (anulus of Zinn) Insertion - anterior half of eyeball medially Origin - medial part of common tendinous ring (anulus of Zinn) Insertion - anterior half of eyeball inferiorlyįunction - depression, adduction, external rotation of eyeball Origin - inferior part of common tendinous ring (anulus of Zinn) Insertion - anterior half of eyeball superiorlyįunction - elevation, adduction, internal rotation of eyeball Origin - superior part of common tendinous ring (anulus of Zinn) ![]() Six extraocular muscles move the eye: superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique and inferior oblique muscles and one other, levator palpebrae superioris, opens the eyelid. Intrinsic ocular muscles which are within the eyeball itself and control how the eyes accommodate.Extraocular muscles that move the eyeballs within the orbit.We made them in a fun and approaching way, so we promise you won't cry: Everything about the anatomy of the lacrimal gland and lacrimal apparatus can be found in these learning materials. So, the function of the lacrimal gland is the production of tears, and it is regulated by the lacrimal nerve, a branch of the ophthalmic nerve (CN V1). But actually, the gland is placed in the lacrimal fossa at the upper part of the superior orbital wall, and its duct opens at the medial part of the orbit causing the tears to run down our nose when we think about how many anatomy pages we have left and it’s already 5 AM. Everyone who has cried at least once, especially because of sleep deprivation that medical college brings, probably thinks that the lacrimal gland is placed in the medial part of the orbit since the tears run from there. The lacrimal gland is a part of the lacrimal apparatus, which besides the gland consists of its numerous ducts, the lacrimal canaliculi, lacrimal sac and nasolacrimal duct. Muscles: Oculomotor (CN III), trochlear (CN IV) and abducens (CN VI) nerves Intrinsic: Sphincter pupillae, dilator pupillae, ciliaris Maxilla, zygomatic bone, frontal bone, ethmoid bone, lacrimal bone, sphenoid bone and palatine boneĬornea, anterior chamber, lens, vitreous chamber and retinaĮxtrinsic: Superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, levator palpebrae superioris Key facts about the orbit and eyes Orbit definitionīony cavity within the skull that houses the eye and its associated structures (muscles of the eye, eyelid, periorbital fat, lacrimal apparatus) This page will discuss the anatomy of the eye and orbit. The orbits are specifically designed to allow these neurovascular structures to pass through its walls, from the cranium on their way to the face. They are placed within the orbits, two cavities in the upper face, in the anterior surface of the head.īesides the eyes, the orbits host several structures that support the eyeballs, including muscles, vessels, nerves and a gland. The eyes are essential for our daily experience, since about 70% of information we gather is by seeing.
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