By pd anatomy of the orbit


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By pd anatomy of the orbit

  1. 1. ???? D FORGOTTEN STORY???? • • • • • • • • When I awoke in hospital in Brighton I was told: 'You must have an operation on your right eye.' ,,I was greatly surprised. Apparently a splinter had passed from the windscreen and entered my eye. Mr. David , the surgeon, was summoned to perform an emergency operation., he did good job but afterwards I learnt that I had lost the lens of the eye, it having dissolved through injury, and The pupil of the eye had been stitched up, leaving me practically without vision. The eye was also out of alignment. It took me a long time to realize I had virtually lost the use of one eye, but even then, never for an instant did I consider I might not be able to play cricket again. With a contact lens in my injured eye I found I could get about 90 per cent vision. The only trouble was it made me see TWO of everything.
  2. 2. A TIGER WITH A SINGLE EYE!!! • What might have happened that day?? • Which all structures got damaged in orbit?? • Who is HE??? Is he really important!!! ??????*any guesses*?????
  3. 3. ANATOMY OF THE ORBIT Presenter:- Pushkar Dhir Moderator:- Dr.Neha Khanduja
  4. 4. INTRODUCTION • Quadrilateral pyramid shaped Bony cavities situated one on either side of root of nose. • Major functions – 1. Provide the socket for the rotatory movements of the eye 2. Protect the eyeballs.
  5. 5. Optical Axis Orbital Axis • Medial wall- parallel & approximately 2.5cm away • Lateral wall-90 degree. • Medial with lateral- 45 degree. • Orbital axis- 22.5 degree, Divergent, Forwards and laterally. 22.5
  6. 6. DIMENSIONS • Entrance height-3.5cm • Entrance width 4-4.5cm
  7. 7. *Depth of orbit varies from 4.4-5cm
  8. 8. BONY ORBIT Composed of 7 bones1. 2. 3. 4. 5. 6. 7. . Ethmoid Frontal Lacrimal Maxilla Palatine Sphenoid Zygomatic
  9. 9. Orbital RIM • Superior orbital rim -> frontal bone. • Inferior orbital rim -> maxillary bone medially and zygomatic bone laterally. • Medial orbital rim -> Frontal process of maxilla • Lateral orbital rim -> Zygoma • In Medial 1/3rd of Superior orbital rim Supraorbital notch. (supraorbital nerve & artery passes to forehead)
  10. 10. Orbital Roof • • 1.Orbital plate of Frontal bone & 2.Lesser wing of sphenoid. Relations- anterior cranial fossa (frontal lobe & meninges),frontal sinus, frontal nerve, trochlear nerve and supraorbital artery.
  11. 11. Nasolacrimal sac & duct •FOSSA FOR THE LACRIMAL GLAND•LOCATION: behind the zygomatic process of the frontal bone TROCHLEAR FOSSA (FOVEA) LOCATION: 4 mm from the orbital margin CONTENTS: insertion of tendinous pulley of Superior Oblique (In sme cases there is a spicule of bone (Spina trochlearis) Landmarks1.Fossa for lacrimal gland. 3.Supraorbital notch. 2. Fovea or trochlear fossa. 4. Optic Foramen(+nt in lesser wing) Applied anat :-Defect in roof- pulsatile proptosis due to transmission of CSF pulsation to orbit.
  12. 12. Cribra orbitalia: -apertures apparent on the medial side of anterior portion of the lacrimal fossa -for veins from diploë to the orbit ; Best marked in the fetus and infant. At JUNCTION OF THE ROOF AND MEDIAL WALL, the suture line lies in proximity to CRIBRIFORM PLATE of ethmoid RUPTURE of dura mater CSF enter orbit/nose.
  13. 13. Branches of infraorbital artery pass via this groove to supply the nasal mucosa. Bleeding may occur 4m these vessels during DCR surgeries Lacrimal bone is easily penetrated during ENDO DCR *If maxillary component is predominenet then its difficult to do EDNO DCR Weber`s Suture 1 2 3 4 Ant.& Post. lacrimal crest Fronto-ethmoidal suture line:- dissection done above this line will lead to cranial cavity
  14. 14. • Front - Backwards- Frontal process of Maxilla, Lacrimal bone , Orbital plate of Ethmoid (Largest), Lesser wing of sphenoid. Applied anatomy1. Thinnest portion of wall - Lamina papyracea (it is component of ethmoid bone). Fractured in blow out fractures. (Thick posteriorly at sphenoid and anteriorly at lacrimal crest.) 2. Infections and neoplasms of ethmoid sinus-orbital cellulitis and proptosis. 3. Weber`s Suture :- Also known as sutura longitudinalis imperfecta Runs parallel to anterior lacrimal crest.
  15. 15. Ant. & Post.ethmoidal sinus is located 24mm &36 mm from anterior lacrimal crest respectively. Ant. & Post. Ehtmoidal arteries pass through it.
  16. 16. CLINICAL SIGNIFICANCE OF MEDIAL WALL • Medial wall extremely fragile (presence of ethmoidal air cells and nasal cavity) • Accidental lateral displacement of medial wall- traumatic hypertelorism • Medial wall provides alternate access route to the orbit through the sinus • Ethmoid - Thinnest bone of the orbit - Vascular connections with ethmoid sinus through foramina - Inflammation in the ethmoid sinus spreads readily to the orbit • Tumours of the nasal cavity can breach the lamina papyracea to involve the orbit • Lacrimal bone can be easily penetrated during endoscopic DCR • During surgery, hemorrhage is most troublesome due to injury to ethmoidal vessels.
  17. 17. ORBITAL FLOOR Shortest orbital wall Traingular •Formed by•Orbital plate of maxilla (major) •Orbital surface of Zygomatic bone (anterolateral) •Orbital plate of Palatine bone
  18. 18. • Landmarks Inferior orbital fissure, end backward in pterygopalatine fossa.  Infraorbital groove (post) and canal (ant) • Applied anatomy- 1. As it is roof of maxillary sinus- 0.5-1mm thick. Maxillary carcinoma invading up in orbit may cause proptosis.
  19. 19. 2. Blow out fracture- infraorbital nerves & vessels usually get involved. C/F:- Diplopia Restricted movements(upgaze) Paresthesia Enophthalmos
  21. 21. • Thickest and strongest. Greater wing of sphenoid and zygomatic bone forms it • Applied anatomy- Anterior half of globe is vulnerable to lateral trauma. • Landmarks-  Whitnall’s tubercle  1. 2. 3. 4. 5. zygomatic bone. 4-5 mm behind lateral orbital rim & 1 cm below frontozygomatic suture line. Structure attaching:Lateral canthal tendon Lateral rectus check ligament. Suspensory ligament of lower eyelid (lockwoods ligament) Orbital septum Lacrimal gland fascia *C/S:Tubercle is spared in maxillary resection in CA, as it gives attachment to lockwood etc, can lead to diplopia if resected.
  22. 22. 2.The Spina recti lateralis :— • Its a small bony projection situated on the inferior margin of the SOF at the junction of its wide and narrow portions. • Gives rise to lateral rectus muscle. 3.Zygomatic Groove • Extent:-From the anterior end of the inferior orbital fissure to a foramen in the zygomatic bone. • Contents: - Zygomatic nerve - Zygomatic vessel. C/S of Lateral Wall • Lateral wall protects ONLY THE POSTERIOR HALF of the eyeball, hence palpation of retrobulbar tumours is easier. • Frontal process of zygoma & zygomatic process of frontal bone protect the globe from lateral trauma- known as facial buttress area. • Just behind the facial buttress area, is the zygomaticosphenoid suture, which is the preferred site for lateral orbitotomy.
  24. 24. *Manner of involvement of nerves helps to predict the site and extent of the lesion. *Also k/a Spenoidal fissure *Structure Passing :(Superior LFT + NAO) *C/S :- Tolosa Hunt Syndrome (Inflammation of the superior orbital fissure and apex  ophthalmoplegia &venous outflow obstruction. *Superior Orbital Syndrome (Rochon-duvigneaud Syndrome)# of SOF  CN involves Diplopia,ophthalmoplegia,exopht halmos,ptosis IOF/Sphenomaxillary Fissure 1.Venous drainage from the inferior part of the orbit to the pterygoid plexus 2.neural branches from the pterygopalatine ganglion 3.zygomatic nerve 4. infraorbital nerve Divisions of III’rd nerve ± VI’th nerve Annulus of Zinn (Purely intraconal lesion) III’rd, IV’th and VI’th nerve Entire length of the fissure involved
  25. 25. Connective Tissue System of Orbit 1. Periorbita/Orbital Periosteum *Loosely adherent to the bones *Sensory innervation by branches of V’th nerve • • Applied Anat:- Tumors and pus collected in the subperiosteal space cause thickening of subperiosteum and can cause proptosis and elevated IOP. Eg- dermoid cyst, epidermoid cyst, mucocele, subperiosteal abcess, myeloma, osteomatous tumors, haematoma and fibrous dysplasia. Plain X- rays most useful in diagnosis. 2. Orbital septal system Includes the connective tissue septa which are suspended from the periorbita to form a complex radial and circumferential interconnecting slings.
  26. 26. 3. TENON’S CAPSULE( FASCIA BULBI OR BULBAR SHEATH) • Dense, elastic and vascular connective tissue that surrounds the globe (except over the cornea). • Begins anteriorly at the perilimbal sclera, extends around the globe to the optic nerve, and fuses with the dural sheath and the sclera. • Separated from the sclera by periscleral lymph space, which is in continuation with subdural and subarachnoid spaces • Applied anatomy1. After enucleation, implants are placed within tenon’s capsule or posterior to it within muscle cone. 2. Inflammatory pseudotumor cause florid tenonitis to cause proptosis.
  27. 27. ORBITAL SPACES CENTRAL SPACE Within the muscle cone Contents1. ON and its meninges. 2. Sup and inf- oculomotor nerve. 3. Abducent 4. Nasociliary 5. Ciliary ganglion 6. Ophthalmic artery 7. SOV 8. Central orbital fat Applied Anat:1. Tumors- axial proptosis. Egcavernous haemangioma, solitary neurofibroma, neurilemmoma, schwannoma, ON glioma SUBTENONS SPACE Space b/w sclera & sub tenon capsule *Pus collected in this space is drained by incision of Tenon’s capsule through the conjunctiva -*Site for drug instillation
  28. 28. • Thanks for listening to anatomy of The ORBIT D orbit!!!!!!...nt dis Grrr…r u one genius.. sleepy…??? Put the right slide Comp: oh…m sry Comp: ok