Orbit bones and their relations
What attaches to the marginal tubercle?
From anterior to posterior: 1. aponeurosis of LPS 2. lateral palpebral lig 3. lateral check ligament
4 nerves that pass through walls/formamina of the orbit?
Infraorbital foramen (infraorbital nerve) Zygomaticofacial foramen (zygomaticofacial nerve) Zygomaticotemporal foramen (zygomaticotemporal nerve) anterior ethmoidal foramen (anterior ethmoidal nerve) Posterior ethmoidal foramen (posterior ethmoidal nerve)
where does the optic canal lie?
Lesser wing of sphenoid
Name 4 structures passing through inferior orbital fissure?
Zygomatic nerve Inferior ophthalmic vein Maxiallary nerve Branches of pterygopalatine ganglion
What runs through the zygomaticofacial foramen?
Zygomaticofacial nerve
What runs through the zygomaticotemporal foramen?
Zygomaticotemporal nerve
3 bones that form the boundary of the pterygopalatine fossa?
anteior: posterior surface of Maxilla Posterior: pteryoid process, great wing of sphenoid Medial: perpendicular plate of palatine bones and sphenoidal process lateral: ptergomaxillary fissure Inferior: pyramindal process of palatine bone
Structures damaged from fracture of mid-orbital floor?
infraorbital canal/foramen infraorbital nerve inferior rectus maxillary sinus
Structures traversing superior orbital fissure within tendinous ring?
"Around 2 Ocular Nerves" Aducent nerve Occulomotor nerve - upper divison Occulomotor nerve - lower division Nasociliary nerve
Structures traversing superior orbital fissure outside tendinous ring?
"LFTS" Lacrimal nerve Facial nerve Trochlear nerve Superior Ophthalmic Vein
Bones forming medial wall of orbit?
"My Little Eye Sits in the orbit" 1. maxilla (frontal process) 2. Lacrimal 3. Ethmoidal 4 Sphenoid (body)
Bones that form the boundary of the inferior orbital fissure?
"bones Mark the Spot" Maxilla Sphenoid (greater wing)
Bones forming the floor of the orbit?
(Zoo Panda's Munch munch) 1. zygomatic bone 2. palatine 3. maxilla (orbital plate)
Bones forming the roof of the orbit?
- Orbtial plate of frontal bone - lesser wing of sphenoid
What runs through the anterior ethmoidal foramen?
- anterior ethmoidal nerve - anterior ethmoidal artery
where does the anterior ethmoidal foramen open?
- arises in frontoethmoidal suture - opens at lateral edge of cribriform plate of ethmoid bone
what happens to the orbtial fascia at the optic canal?
- attached to dural sheath of optic nerve
What does the orbital fascia form posteriorly?
- common tendinouos ring - gives origins for the tendons for the 4 rectus muscles - formed around optic canal and medial end of superior orbtial fissure
Where do the posterior ethmoidal nerves and vessles supply?
- ethmoidal sinuses?
Relations to the roof of the orbit?
- frontal air sinuses (ant med) - frontal lobe
Relationship of the optic canal to the sinuses?
- generally sphenoid and ethmoid sinus lie medial to optic canal - anatomical variation: may lie superior and lateral to canal
What forms the boundary of the inferior orbital fissure?
- great wing of sphenoid - orbital plate of maxilla
What forms the boundary of the superior orbital fissure?
- greater wing of sphenoid - lesser wing of sphenoid
Structures within the bones of the floor of the orbit?
- inferior orbital fissure - infraorbital groove --> infraorbital canal
What runs through the infraorbital canal?
- infraorbital nerve - infraorbital artery - infraorbital vein
what does the inferior orbtial fissure connect the orbit to?
- infratemporal fossa - pterygopalatine fossa
Structures within the bones of the roof of the orbit?
- lacrimal fossa - supraorbital notch - trochela fossa (4mm post)
What attaches to the superior orbtial fissure?
- lateral rectus (sharp spine) - common tendinous ring
Orbital fasica (Periorbita)
- loosely attached to orbital bones - continuous through foramina and fissures - adherent to bone at sutures and foramina - at orbital margin, continuous with periosteum of external surface - forms orbital septum of eyelids
Relations of the floor of the orbit?
- maxillary sinus - inferior orbital canal
Relations of the medial wall?
- nasal cavity - ethmoidal sinuses - sphenoid sinus
Is the inferior orbital fissure open?
- no - bridged by thin layer of smooth muscle (Muscle of Muller - embedded in orbital fascia)
what connects the orbit to the medial cranial fossa?
- optic canal - superior orbtial fissure
what runs through the optic canal?
- optic nerve (+meninges) - ophthalmic artery (+sympathetic plexus)
what runs through the posterior ethmoid sinus?
- posterior ethmoidal nerve - posterior ethmoidal artery
What does the inferior ophthalmic vein drain into?
- pteryoid venous plexus
Structures within the bones of the lateral wall of the orbit?
- superior orbital fissure - marginal tubercle - zygomaticotemporal foramen - zygomaticofacial foramen
Where is the orbital fascia continuous with the endosteal layer of the dura?
- superior orbtial fissure - optic canal - anterior ethmoidal canal
Relations to the lateral wall of the orbit?
- temporal fossa (ant) - temporal lobes (post) - middle cranial fossa
what forms the orbital septum?
- the orbital fascia - at the eyelids
what bones from the lateral wall of the orbit?
- zygomatic bone - greater wing of sphenoid
Bones forming the orbit? (7)
1. Frontal 2. Zygomatic 3. Maxilla 4. Sphenoid 5. Palatine 6. Lacrimal 7. Ethmoid
which bones form the boundary of the lacrimal groove?
1. Lacrimal bone (posterior) 2. Frontal process of maxilla (anteriorly)
Orbital margins/surface antaomy?
1. frontozygomatic suture 2. supraorbital notch 3. trochlea 4. lateral palpebral ligament 5. medial palpebral ligament 6. anterior lacrimal crest 7. lacrimal groove 8. posterior lacrimal crest 9. infraorbital foramen (5mm inferior)
Structures within the bones of the medial wall of the orbit?
1. lacrimal groove 2. anterior and posterior lacrimal crests 3. anterior ethmoidal foramen 4. posterior ethmoidal foramen
Where does the orbtial fascia split and what structures does it enclose?
1. lacrimal groove -> lacrimal sac 2. lacrimal fossa -> lacrimal gland
how long is the optic canal?
4-10mm
What holds the trochlea?
A process given off by the orbital fascia
Nerve supply of orbital fascia?
Branches of trigeminal nerve
