1. 2 nd Professional MBBS Batch (C)

3.  Bilateral structure  Formed by the combination of seven bone-known as Bony orbit. i.e  Maxilly bone  Zygomatic bone  Palatine bone  Frontal process of maxilla  Lacrimal bone  Sphenoid bone &  Ethmoid bone  These bones gives pyramid shape

4.  The following bones take part in their formation:  Superior margin : frontal bone and sphenoid.  Inferior margin: maxillary bone, palatine and zygomatic.  Medial margin: ethmoid, lacrimal bone, sphenoid (body of) and maxilla.  Lateral margin: zygomatic and sphenoid (greater wing)

5.  Formed front to back by the;  Frontal process of maxilla  Lacrimal bone  Orbital plate of Ethmoid bone  Body of Sphenoid bone

6.  Triangular in Shape  It is formed by;  Anteriorly ; by Zygomatic bone  Posteriorly ; by greater wing of sphenoid bone

7.  Traingular in shape  It is formed mainly by the Orbital Plate of frontal bone & Smaller contribution of lesser wing of Sphenoid bone

8.  Triangular in shape  Shortest of the margin  Formed by Three bones- i.e,  Medially: By Orbital surface of maxillary bone  Laterally: By Orbital surface of Zygomatic bone  Posteriorly: By Palatine bone

9.  Antero-lateral part of inferior margin has a depression called Lacrimal fossa for Lacrimal gland  Lacrimal gland continually release fluid-which cleans & protect the eye’s surface and it lubricate & moisten.  The Lacrimal secretion is commonly Known as ‘’Tears’’

10.  Two anterior open end of the orbit is referred to as base of the orbit  It is bounded by the orbital margin  These margin are formed by a ring of compact bone  It gives attachment to the septum orbital

11.  It is a membranous sheet that act as the anterior boundary of the orbit.  It extends from orbital rims to the eyelids  It from the fibrous portion of the eyelids

12.  Eye ball  Optic Nerve  Extra ocular muscle  Lacrimal apparatus  Adipose tissue  Orbital fascia  Nerves & vessel that supplies these structures

13.  Orbital apex is the posterior end of the orbit  Here four orbital walls are converge  Apex has two orifices-i.e,  Optic canal &  Superior orbital fissure  Orifices are situated in the sphenoid bone (where greater wing & lesser wing meet each other)

14. OPTIC CANAL SUPERIOR ORBITAL FISSURE  Average length is 06-11mm  Connect orbit to the middle cranial fossa  Transmit optic nerve & ophthalmic artery  Comma shape aperture in the orbital cavity  Bounded by greater & lesser wing of sphenoid bone  The fissure is divided into three parts by tendinous ring,  Upper Orbital fissure  Medial Orbital fissure  Lower Orbital fissure

15. Structures passes through the upper to lateral part are;  Lacrimal nerve,  Frontal nerve,  Trochlear nerve,  Superior ophthalmic vein &  Recurrent branch of ophthalmic artery

16.  The medial part of fissure (within the tendinous ring) transmit;  Superior & Inferior division of the oculomotor nerve,  The nasociliary branch of ophthalmic division of the trigeminal nerve & the abducent nerve

17.  The lower & medial part of the fissure transmit the inferior ophthalmic vein

18. Lacrimal apparatus is involved in the  Production,  Movement &  Drainage of fluid from the surface of the eyeball

19. There are four part of lacrimal apparatus  The lacrimal gland & its duct  The Lacrimal canaliculi  The Lacrimal sac &  The Naso-lacrimal duct

20.  Consist of large orbital part and a small palpebral part- continuous with each other  Situated above the eyeball in the anterior & upper part of the orbit  The gland is open into the lateral part of the superior fornix of the conjuctiva (mucous membrane covers the front of eye & lines the inside of the eyelids) by 12 ducts

21.  Tears circulate across the cornea & accumulate in the Lacus Lacrimalis  Then enter into Canaliculi Lacrimalis through the Puncta Lacrimalis  Further the Canaliculi Lacrimalis open onto Lacrimal sac

22.  Naso-lacrimal duct is about 0.5 inches (1.3cm) long  Emerge from the lower end of Lacrimal sac  It open into anterior meatus of nose-has fold known as Lacrimal fold  The lacrimal fold prevent air from being forced up the duct into the lacrimal sac on blowing the nose