|  | | | | | | | | | | Orbital volume and dimensions: = 30 cc, 35(Height) x 45(Width) x 45 mm(medial wall depth), globe 25 x 25 mm
Bones: (F)rontal, (M)axillary,(Z)ygomatic, (L)acrimal, (E)thmoid, (P)alatine, (S)phenoid
| | | |
Roof : - Bones
- Frontal
- Lesser wing of sphenoid
- Cotnents
- lacrimal gland fossa
- trochlea 4mm posterior to margin for superior oblique tendon
- supraobital notch/foramen
- Clincal Correlations
| - Bones
- Maxillary
- Lacrimal
- Ethmoid - thinest
- Sphenoid
- Contents
- lacrimal sac fossa
- cribiform plate is medial to anterior orbit at the level of fronto-ethmoidal suture
- Clincal Correlations
- Nasoclacrimal duct obstructions./tumors/DCRs
- Medial wall fractures
- subperisteal abscess
- Orbital cellulitis/proptosis from ethmodial extension
| Floor: - Bones
- Maxillary- second thinnest, thins posteriorly
- Zygoma
- Palatine
- Conents
- infraorbital foramen
- inferior oblique origin
- slopes 20 degrees down
- suspensory ligament of eyeball,
- Clincal Correlations
- subperiosteal abscess
- blow-out fracturs
| Lateral wall: - 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
- Clincal Correlations
- Tripod fractures
- Ruptured globes
- Lateral tarsal strips
- adjacent to middle cranial fossa, temporal fossa, and pterygopalatine fossa
|
|
- The medial orbital walls are nearly parrallel and are 25 mm apart
- The orbit is widest not at its entrance, but 1 cm from the orbital rim
- Holes & Fissures
| Holes & Fissures
| | | | | | | | | Fissures | Holes/Notches/Canals | Superior orbital fissure (SOF): 22 mm long separates greater wing of spenoid 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: supeior ophthalmic vein
Inferior orbital fissure (IOF) located between lateral orbital wall and the orbital floor Transmits V2 ( maxillary) , pterygoid nerves nerve arising from pterygopalatine ganglion infraorbital nerve (a branch of V2) enters the infraobital groove and infraorbital canal for sensation to lower eyelid, cheek, upper lid, upper teeth Venous system inferior ophthalmic vein
| Nasolacrimal canal 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 (V2)
Ethmoidal foramina anterior ethmodial 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 OTIC STRUT Transmits. Ophthamic nerve, ophthalmic artery, sympathtic nerves
|
|
| | AXIAL ORBITAL MRI | | | | |
|
|
Click above to visit the POREX SURGICAL website and learn about MEDPOR®
|
