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= 30 cc, 35(Height) x 45(Width) x 45 mm(medial wall depth), globe 25 x 25 mm
(F)rontal, (M)axillary,(Z)ygomatic, (L)acrimal, (E)thmoid, (P)alatine, (S)phenoid
- Bones
- Frontal
- Lesser wing of sphenoid
- Contents
- lacrimal gland fossa
- trochlea 4mm posterior to margin for superior oblique tendon
- Supraorbital notch/foramen
- Clinical Correlations
- Bones
- Maxillary
- Lacrimal
- Ethmoid - thinnest
- Sphenoid
- Contents
- lacrimal sac fossa
- cribiform plate is medial to anterior orbit at the level of fronto-ethmoidal suture
- Clinical Correlations
- Nasoclacrimal duct obstructions./tumors/DCRs
- Medial wall fractures
- subperisteal abscess
- Orbital cellulitis/proptosis from ethmodial extension
- Bones
- Maxillary- second thinnest, thins posteriorly
- Zygoma
- Palatine
- Contents
- infraorbital foramen
- inferior oblique origin
- slopes 20 degrees down
- suspensory ligament of eyeball
- Clinical Correlations
- subperiosteal abscess
- blow-out fractures
- Bones
- Zygomatic bone
- Greater wing of sphenoid
- Contents
- lateral orbital tubercle is 11mm below F-Z suture,
- serves as attachment of check ligament of lateral rectus
- Clinical Correlations
- Tripod fractures
- Ruptured globes
- Lateral tarsal strips
- adjacent to middle cranial fossa, temporal fossa, and pterygopalatine fossa
- The medial orbital walls are nearly parallel and are 25 mm apart
- The orbit is widest not at its entrance, but 1 cm from the orbital rim
- Superior orbital fissure (SOF):
- 22 mm long
- separates greater wing of sphenoid from lesser wing of sphenoid
- transmits third, fourth, sixth and V1 AND SYMPATHETIC FIBERS
- lateral rectus origin separates into superior and inferior divisions
- Superior division transmits lacrimal, frontal and trochlear nerves
- Inferior division transmits superior and inferior divisions of CN III, nasociliary branch of CN V, CN IV, superior ophthalmic vein, and sympathetic nerve plexus
- Venous system: superior ophthalmic vein
- Inferior orbital fissure (IOF )
- L ocated between lateral orbital wall and the orbital floor
- Transmits V 2 ( maxillary) , pterygoid nerves nerve arising from pterygopalatine ganglion
- infraorbital nerve (a branch of V 2 ) enters the infraobital groove and infraorbital canal for sensation to lower eyelid, cheek, upper lid, upper teeth
- Venous system inferior ophthalmic vein
- Nasolacrimal canal Nasolacrimal canal
- lacrimal sac fossa to the inferior meatus
- separates greater wing of sphenoid from lesser wing of sphenoid
- transmits third, fourth, sixth and V1 AND SYMPATHETIC FIBERS
- lateral rectus origin separates into superior and inferior divisions
- Superior division transmits lacrimal, frontal and trochlear nerves
- Inferior division transmits superior and inferior divisions of CN III, nasociliary branch of CN V, CN IV, superior ophthalmic vein, and sympathetic nerve plexus
- Venous system: superior ophthalmic vein
- Supraorbital foramen/notch
- transmits blood vessels
- supraorbital nerve
- Anterior/posterior ethmoidal foramen: transmits ethmoidal blood vessels and nerve
- Zygomatic foramen: transmits zygomaticofrontal and zygomaticotemporal nerves, zygomatic artery
- Nasolacrimal duct (NLD): exits into inferior meatus
- Infraorbital canal: transmits infraorbital nerve (V 2 )
- Ethmoidal foramina
- anterior ethmoidal artery
- posterior ethmoidal artery
- allows infections and neoplasms to enter to orbit from the sinuses
- Optic Canal
- 8-10 mm long
- located within the less wing of sphenoid
- separated from SOF by OPTIC STRUT
- Transmits. Ophthalmic nerve, ophthalmic artery, sympathetic nerves
- Optic foramen is 6.5 mm wide: it may be enlarged in the presence of optic nerve glioma; 1 mm of asymmetry between right and left is abnormal
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