Orbit ppt.pptx Ramji pandey consultant optometrist

PPT

1. ORBIT- ANATOMY Mahendra Singh

2. The anterior border of the anterior cranial fossa is formed by the frontal bone of the skull.

3. Location: The maxillary sinuses are situated on either side of the nose, deep within the facial bones. They are positioned behind the cheeks and extend upward toward the eye sockets.

4. The bony orbits are quadrangular, truncated pyramids. situated between the anterior cranial fossa above and the maxillary sinuses below. Each orbit is a pear-shaped cavity, the stalk of which is the optic canal, and measures about 40 mm in height width, and depth.

5. (1) Frontal, (Topmost bone) (2)Zygomatic (largest & hard bone)) (3) Maxilla (4) Sphenoid, (5) Palatine (6) Ethmoid,(thinnest) (7) Lacrimal. It is formed by portions of seven bones Supra-orbital notch at junction of median 1/3 & lateral 2/3 and transmit supra-orbital vessels and nerves

6. Medial (Thinnest wall) lateral, (Thickest wall) superior Inferior It has four walls

7. The medial walls of the two orbits are parallel to each other. and, being the thinnest, are frequently fractured during injuries as well as during orbitotomy operations, this also accounts for ethmoiditis being the most commonest cause of orbital cellulitis Medial wall

8. Roof of the orbit is triangular in shape and is formed mainly by the orbital plate of frontal bone. Roof

9. (floor) is triangular in shape and being quite thin is commonly involved in blow-out fractures and is easily invaded by tumors from the maxillary antrum. lnferiororbital wall

10. is triangular in shape. It covers only posterior half of the eyeball. Therefore palpation of the retrobulbar tumors is easier from this side. Because of its advantageous anatomical position, a surgical approach to the orbit by lateral orbitotomy is popular. Lateral wall of the orbit

11. is the anterior end which opens in the face and is bounded by thick orbital margins. Base of the Orbit

12. It is the posterior end of the orbit where the four orbital walls converge. It has two orifices, the optic canal which transmits the optic nerve and ophthalmic artery, and the superior orbital fissure which transmits a number of nerves, arteries and veins Orbital apex

13. It is a thin but tough connective tissue membrane lining the various intra-orbital structures. Though it is one continuous tissue, but for the descriptive convenience, it has been divided into fascia bulbi,muscular sheaths, imerrnuscular septa, membranous expansions of the extraocular muscles, and ligament of Lockwood Orbital fascia

14. envelopsthe globe from the margins of the cornea to the optic nerve. Its lower part is thickened to form a sling or hammock on which the globe rests; this is called'suspensory ligament of Lockwood. Fascia bulbi (Tenon's capsule)

15. Eye ball Orbital fat Connective tissue system Blood vessels Nerves Extraocular muscles Contents of orbit

16. The volume of each orbit is about 30 cc. Approximatelyone -fifth of it is occupied by the eyeball. Othercontents of the orbit incl ude : part of optic ne rve,extraocular muscles, lacrimal gland, lacrimal sac,ophthalmic artery and its branches, third, fourth andsixth cranial nerves and ophthalmic and maxillarydivisions of the fifth cranial nerve, sympathetic nerve,orbital fat and fascia CONTENTS OF ORBIT

17. apex

18. Thank you