Orbit | Boundaries | Fissures and Foramina | Relations | Contents
ฝัง
- เผยแพร่เมื่อ 9 ก.ย. 2024
- Features
The orbits are pyramidal cavities,
situated one on each side of the root of the nose.
They provide sockets for rotatory movements of the eyeball.
The long axis of the each orbit passes backwards and medially.
The medial walls are parallel to each other at a distance of 2.5 cm
but the lateral walls are set at right angles to each other.
Contents
I. Eyeball: Eyeball occupies anterior one-third of orbit. 2. Fascia: Orbital and bulbar.
3. Muscles: Extraocular and intraocular.
4. Vessels: Ophthalmic artery, superior and inferior ophthalmic veins, and lymphatics.
5. Nerves: Optic, oculomotor, trochlear and abducent;
branches of ophthalmic and maxillary nerves, and sympathetic nerves. 6. Lacrimal gland:
7. Orbital fat.
Visual Axis ond Orbital Axis
Axis passing through centres of anterior and posterior poles of the eyeball is known as visual axis. It makes an angle of 20 - 25 ̊ with the orbital axis,
i.e. line passing through optic canal and centre of base of orbit, i.e. opening on the face.
Orbital Fascia or Periorbita
It forms the periosteum of the bony orbit.
Due to the loose connection to bone, it can be easily stripped.
Posteriorly, it is continuous with the dura mater and with the sheath of the optic nerve. Anteriorly, it is continuous with the periosteum lining the bones around the orbital margin. There is a gap in the periorbita over the inferior orbital fissure.
This gap is bridged by connective tissue with some smooth muscle fibres in it.
These fibres constitute the orbitalis muscle.
a. At the upper and lower margins of the orbit, the
orbital fascia sends off flap-like continuations into
the eyelids. These extensions form the orbital septum.
b. A process of the fascia holds the fibrous pulley of the tendon of the superior oblique muscle in place.
c. Another process forms the lacrimal fascia which bridges the lacrimal groove.
Fascial Sheath of Eyeball of Bulbar Fascia
1. Tenon's capsule forms a thin, loose membranous sheath around the eyeball, extending from the optic nerve to the sclerocorneal junction or limbus.
• It is separated from the sclera by the episcleral space which
is traversed by delicate fibrous bands.
• The eyeball can freely move within this sheath.
2. The sheath is pierced by:
a. Tendons of the various extraocular muscles.
b. Ciliary vessels and nerves around the entrance of the optic
nerve.
3. The sheath gives off a number of expansions.
a. A tubular sheath covers each orbital muscle.
b. The medial check ligament is a strong triangular expansion from the sheath of the medial rectus muscle; it is attached to the lacrimal bone.
c. The lateral check ligament is a strong triangular expansion from the sheath of the lateral rectus muscle; it is attached to the zygomatic bone
4. The lower part of Tenon's capsule is thickened, and is named the suspensory ligament of the eye or the suspensory ligament of Lockwood .
• It is expanded in the centre and narrow at its extremities, and is slung like a hammock below the eyeball.
• It is formed by union-of the margins of the sheaths of the inferior rectus and the inferior oblique muscles with the medial and lateral check ligaments.
Follow me in blogspot - human-anatomyl... Follow me in blogspot - human-anatomyl... _________________________________________________________________________________________________________________ Visit my blogs - humananatomyon...
Contact me @ t.me/humananat...
Amazing
Thanks
Amazing video 👌😀❤️
Thank you 🤗
Thank you! These videos are extremely helpful!
Glad you like them!
Thanks a lot mam for this video
Most welcome 😊
Indeed
What is malaligment of orbits???
That, due to any facial skeleton developmental anomaly
There is no word to describe your explanation mam
Just stunned to see the 3d..
Woww
Awesome mam💪
Thank you very much
My pleasure 😊
Very helpful😊😊
Thank you 😊
Mam thanks for following ak datta...U made it easy for me🥰Never stop making videos mam
Thank you and I will never stop
Thankyou mam
Most welcome 😊
Thanks it helped alot
Glad it helped
True that
Tysm mam helped me a lot
Most welcome 😊
Thankyou mam...
Most welcome 😊
Mam I need guidance from you in anatomy
I am a first year MBBS student
in few days there will be an exam for us for complete neuroanatomy and head and neck
I want to ask you a question that should I only stick to your videos or should I read side-by-side from the book because there is not much time left in the exam. Hardly one week.
I'm really worried and need your guidance.
I have already joined your google classroom.
My preparation is not much and i also don't have any notes what so ever.
Please mam help.
It would be helpful if you can make a video on important topics about these as soon as possible.
Hi
U have to read the topics in the book and then follow the videos and PDFs whatever is there.
Stick on one way and start preparing.
When u hear repeatedly, You will remember the things. That's the main reason, I started the videos.
Nothing to worry.
Study well.
Anything U want my help, Comment me down.
Pleasure to help u
Ma’am pls make more videos of neuro anatomy . Will help us study for online exams🙏🙏
Yes, will do!
Human Anatomy Lessons thank you so much man🙏 pls do important and tough topics of neuro anatomy , your videos are very helpful
Thank you so much, Mam your videos makes me understand the topics very easily.
I spend a lot of time in searching a good explanation video and you channel is the best of best.
But I only found head n neck videos please mam suggest me some good channels on upper, lower limb, abdomen and same on biochemistry and physiology.
Please mam my exam are ahead and iam still not prepared.
All the best
I dont have any idea about other channels.
I have seen anatomy zone.. U can check that.
Hello mam , can you please tell about the study sources from where you collected this helpful ophthalmology stuff. Did you get help from Snell's ocular anatomy as well?
It’s from an application software 3d4 complete anatomy. Other sources are from Grays Dutta and Netters
Mam is everything here enough for 1 st year mbbs, I think u follow bdc so it is very easy to study side by side watching ur videos and reading bdc,..... Ur following bdc right mam?
I refer grays, AK Dutta and bdc too
I don’t stick on one book
@@HumanAnatomyLessons ok mam thanks
Larynx anatomy if you have upload us thanks
I have to make. Sure, will do!
Thansk ma'am
U told they form right angle when they meet what is the meeting point pls say mam
The axis form right angle u can see the video u will see the image
@@HumanAnatomyLessons already saw vedio sooo axis line which is moving toward median wall right
The axis line long the lateral walls of the orbit. check this image.
photos.app.goo.gl/F1rjZGGqymZFFJ6T9
Salam ,
Mam please add me in google classroom head and neck anatomy , histology , neuroanatomy and all other session .thank u so much
join using the code
for head and neck - un5kkup
neuroanatomy - oipflg2
histology - pw5xq3f
upper limb - 7mvk6ub
MCQs - d3epobp