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Surgical anatomy of orbit 1 /certified fixed orthodontic courses by Indian dental academy
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Surgical anatomy of orbit 1 /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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  • 1. SURGICAL ANATOMY OF INDIAN DENTAL ACADEMY ORBIT Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. Introduction  Orbit is a Pyramidal shaped bony cavity, situated one on each side of the root of the nose.  They provide sockets for the rotatory movements of the eyeball, as well as protect them.  The Orbit is an anatomical region which is of clinical and surgical interest to many disciplines…… www.indiandentalacademy.com
  • 3. SHAPE AND DISPOSITION • Each Orbit resembles a 4 sided Pyramid, laid on each side.. Thus it has: • Apex • Base • Four walls: Roof, Floor, Lateral and Medial walls • The long axis of the Orbit passes backwards and medially. The Medial walls are parallel to each other and the Lateral walls are at right angles to each other. www.indiandentalacademy.com
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  • 7. Roof of Orbit • Formed by: Orbital plate of Frontal bone and completed posteriorly by the Lesser Wing of Sphenoid. • It separates the Orbit from the Anterior cranial fossa. The Frontal air sinus may extend into its anteromedial part. • Named structures: Lacrimal fossa, Optic canal, Trochlear fossa( it provides attachment to the fibrous pully for the tendon of Superior Oblique muscle). www.indiandentalacademy.com
  • 8. Lateral wall of Orbit • Thickest and Strongest of all the walls. • Formed by: Anterior surface of Greater wing of the Sphenoid bone and orbital surface of Frontal process of Zygomatic bone. • Sphenoid separates the Orbit from the Middle Cranial fossa, Zygomatic bone separates it from Temporal fossa. • Named structures: Superior Orbital Fissure, foramen for the Zygomatic nerve, Whitnalls tubercle (it provides attachment to the Lateral check ligament of the Eye ball). www.indiandentalacademy.com
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  • 10. Floor of Orbit • It slopes upwards and medially to join the Medial wall. 0.5mm in thickness. • Its very weak,as it is thin and also due to the presence of Infra Orbital groove and canal. • Common site for BLOW OUT # • Formed by: Orbital surface of Maxilla, Orbital part of Zygomatic bone, Orbital process of Palatine bone. • Floor separates Orbit from Maxillary Sinus. • Named structures: Inferior orbital fissure, Infra Orbital groove, origin of Inferior Oblique muscle. www.indiandentalacademy.com
  • 11. Medial wall of Orbit • Thinnest of all the walls. • Formed by: Frontal process of Maxilla, Lacrimal bone, Orbital plate of Ethmoid, Body of Sphenoid. • Lacrimal groove- separates the Orbit from Nasal cavity, Ethmoid- separats Orbit from Ethmoidal air sinus, Sphenoidal sinuses are separated from Orbit by a thin layer of bone. • Named structures: Lacriaml groove, Ant and Post Ethmoidal foramina. www.indiandentalacademy.com
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  • 14. CONTENTS OF THE ORBIT • Eyelids- Movable curtains which protect the eyes from bright light and foreign particles. • They are attached to the margins of the orbital opening. • Cross section reveals skin, superficial fascia, Cilia, Zeis’s glands (modified sebaceous glands), Moll’s glands (modified sweat glands), Meibomian glands( sebaceous glands). • Tarsal plates form the exoskeleton of the eyelids and they give stiffness to the eyelids.. www.indiandentalacademy.com
  • 15. • Peri-Orbital fat : Acts as a frictionless packing material providing a cushion upon which the muscles can rotate the eyeball within the Tenon’s capsule. • Conjunctiva : Bulbar & Palpebral types. Palpebral conjunctiva is found behind the eyelids, its thick, opaque, highly vascular and firmly adherent to Tarsal plates. Bulbar conjunctiva is thin, transparent and loosely attached to sclera www.indiandentalacademy.com
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  • 18. Lacrimal Apparatus • Structures concerned with the secretion and drainage of the Lacrimal fluid constitute Lacrimal Apparatus. They include.. 1)Lacrimal Gland : Serous gland situated superolaterally in the Orbit… “J “ shaped organ embracing the Levator Palpebrae Superioris muscle. It has a Palpebral part( containing all the ducts) and Orbital part. Removal of the Palpebral part is as good as removing the whole gland. www.indiandentalacademy.com
  • 19. • The gland has about dozen ducts which pierce the Conjunctiva of the upper lid and open into Conjunctival sac near superior Fornix. Lacrimal fluid keeps the Cornea and Conjunctiva clean, moist and is drained into the Lacrimal Canaculi by periodic blinking of the eyelids. Excess fluid flows as Tears. 2)Conjunctival Sac: The space b/w palpebral and bulbar conjunctiva, filled with lacrimal fluid. Reflection of palpebral conjunctiva reveals the Fornix. www.indiandentalacademy.com
  • 20. • 3)Lacrimal Puncta and Canaliculi: Each canaliculi begins at th Lacrimal Punctum, and is about 10mm long. Both the canaliculi open close to each other in the lateral wall of the lacrimal sac behind the Medial Palpebral Ligament. 4)Lacrimal Sac: It’s a membranous sac 12mm long and 5 mm wide,situated in the lacrimal groove, continuous with the NasoLacrimal duct. Inflammation of the Lacrimal Sac: DACRYOCYSTITIS… 5)Nasolacroimal Duct: Membranous passage 18mm long, runs downwards and laterally to open into the Inferior Meatus of the Nose, controlled by the Valve of Hasner. www.indiandentalacademy.com
  • 21. • Functions of Tear fluid : - keeps the Cornea moist and clean - provides nourishment to Cornea - Bactericidal ( Lysozyme) www.indiandentalacademy.com
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  • 23. ORBITAL FASCIA • Orbital fascia/ Periorbita forms the Periosteum of the bony Orbit. • It can be easily stripped off from the bone due to its loose connection. • Posteriorly, it is continuous with the Dura mater and with the sheath of Optic nerve. Anteriorly it is continuous with the Periosteum lining the bones around Orbital margin. • A processes of the fascia holds the fibrous pulley of the tendon of S.O.M, another process forms the Lacrimal fascia, which bridges Lacrimal groove. www.indiandentalacademy.com
  • 24. BULBAR FASCIA • It’s the Fascial sheath of the Eye ball… • Tenon’s Capsule forms a thin loose membranous sheath around the eyeball extending from Optic nerve to Sclero-Corneal junction.It is separated from sclera by the Episcleral space • Eyeball moves freely within this sheath. • The lower part of Tenon’s capsule is thickened and is named Suspensory Ligament of Lockwood formed by the union of margins of the sheath of Inferior rectus and the Inferior oblique with the medial and lateral check ligament www.indiandentalacademy.com
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  • 27. EXTRAOCULAR MUSCLES • VOLUNTARY MUSCLES - 4 RECTI MUSCLES: Superior Rectus, Inferior Rectus, Medial Rectus, Lateral Rectus. - 2 OBLIQUE MUSCLES: Superior Oblique, Inferior Oblique. -Levator Palpebrae Superioris • INVOLUNTARY MUSCLES - Superior Tarsal Muscle - Inferior Tarsal Muscle - Orbitalis muscle www.indiandentalacademy.com
  • 28. ORIGIN & INSERTION • 4 Recti Muscles arise from Common Annular Ring (Tendinous Ring of Zinn). It encloses the Optic canal and middle part of Superior Orbital fissure. • Recti muscles are inserted into Sclera, little posterior to Limbus.The average distances of insertion from Cornea are: Superior7.7, Inferior-6.5, Medial-5.5, Lateral-6.9mm. www.indiandentalacademy.com
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  • 31. • Superior Oblique muscles arises from the body of the Sphenoid, Superomedial to the Optic canal. • The Tendon of Superior Oblique muscle passes through a Fibrocartilage pulley attached to the Trochlear fossa of the Frontal bone. • It is inserted into the Sclera behind the equator of the Eyeball, b/w the Superior Rectus and the Lateral Rectus. www.indiandentalacademy.com
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  • 33. • Inferior Oblique muscle arises from the Orbital surface of the Maxilla, lateral to the Lacrimal groove. The muscle is situated near the anterior margin of Orbit. • It is inserted close to the Superior Oblique, a little below and posterior to the latter. www.indiandentalacademy.com
  • 34. • Levator Palpebrae Superioris arises from the Orbital surface of the lesser wing of Sphenoid. • It is inserted into anterior surface of the superior tarsus and into the skin of upper eyelid. www.indiandentalacademy.com
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  • 40. NERVE SUPPLY • Superior Oblique muscle: Trochlear nerve. • Lateral rectus: Abducent nerve. • Superior, Inferior, Medial recti , Inferior Oblique &Levator Palpebrae superioris: Oculomotor nerve. www.indiandentalacademy.com
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  • 42. ACTIONS OF MUSCLES • Levator Palpebrae Superioris : Elevation of upper eyelid. • Superior Rectus : Upward rotation, Medial rotation, Intortion. • Inferior Rectus : Downward rotation, Medial rotation, Extortion. • Medial Rectus : Medial rotation. • Lateral Rectus : Lateral rotation. • Superior Oblique : Downward rotation, Lateral rotation, Intortion. • Inferior Oblique : Upward rotation, Lateral rotation, Extortion. www.indiandentalacademy.com
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  • 46. NERVES &VESSELS • Ophthalmic artery • Superior & Inferior Ophthalmic veins • Nerves : -Optic nerve -Oculomotor nerve -Trochlear nerve -Abducent nerve -Lacrimal nerve -Frontal nerve -Nasociliary nerve -Infraorbital nerve -Zygomatic nerve www.indiandentalacademy.com
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  • 50. APPLIED ANATOMY OF ORBIT  Orbit:= Outer frame(thick) & Inner frame (thin).  Outer frame dissipates forces around Orbit rather than transmitting inside, so we see Zygoma #s more frequently in this region.  Majority of Orbit is filled with Fat, only 40% is globe, so cushioning effect.  Orbit is well protected by Frontal, Ethmoidal and Maxilary sinuses.  Optic foramen is well protected by the strong Lesser wing of Sphenoid, so the juxtaposition of the paper thin bone of Ethmoid with the dense bone surrounding the optic foramen diverts the line of # away from the Optic foramen and thus minimising the risk of blindness. www.indiandentalacademy.com
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  • 52. • Collection of blood in the layer of Loose Connective tissue (due to blow to the skull) causes generalised swelling of scalp, which slowly extends into the root of the nose and the eyelids due to gravity causing “ BLACK EYE / CIRCUMORBITAL ECCHIMOSIS”. This occurs because Frontalis muscle has no bony attachments. www.indiandentalacademy.com
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  • 55. CONCLUSION • With these complications pertaining to the Orbit, it is more so important for a Maxillofacial Surgeon to understand the Anatomy of Orbit & correctly diagnose and treat these discrepancies in order to reduce the morbidity… PRITHVI www.indiandentalacademy.com
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