Orbital Contents Flashcards
What six general things does the bony orbit contain?
The globe, CT, EOMs, nerves, vessels, and fat
What is the globe?
The eyeball, consisting of 3 tunics and 3 chambers
What are the three tunics of the globe?
Outer fibrous, middle vascular, inner neural
What are the three chambers within the globe?
Anterior, posterior, and vitreous
What is tenon’s capsule?
Aka bulbar fascia, CT covering sclera and EOM tendon insertions, barrier b/w globe and contents of orbit, prevents orbital infections from entering globe
What is tenon’s capsule continuous with?
Sclera/conj at the limbus and dural sheath of optic nerve
What are the four layers of sclera?
Sclera, episclera, tenon’s capsule, conjunctiva (all continuous with cornea at limbus)
What is the orbital septum?
Aka palpebral fascia, dense CT extends the entire rim of the orbit to the tarsal plate, separates the eyelids and lacrimal sac from orbit and keeps orbital fat in place
What connective tissue prevents facial/eyelid/nasolacrimal system infections from entering the orbit?
Orbital septum
What is the orbital septum continuous with?
Periosteum at superior and inferior orbital rim
What CT is the anterior barrier of the orbit?
Orbital septum
What CT prevents orbital infections from entering the globe?
Tenons capsule
What is the periorbita?
Aka orbital fascia or periosteum, dense CT covering the bones or the orbit
What is the periorbita continuous with?
Periosteum of facial bones and orbital septum anteriorly, dural sheath of optic nerve and forms common tendinous ring posteriorly
What is whinall’s ligament?
Transverse(horizontal) dense CT in superior orbit, provides support and maintains spatial relationships b/w structures in superior orbit
What forms whitnall’s ligament?
Condensation of levator muscle, where muscle fibers end and levator aponeurosis begins (tendon)
What is Lockwood’s ligament?
Transverse dense CT in inferior orbit, support, maintains spatial relationships b/w an anatomical structures in inferior orbit
What does lockwood’s contribute to?
Capsulopalpebral fascia (dense CT that moves lower lid)
What is the medial check ligament?
Transverse dense CT that is an expansion of the sheath of the medial reclusive and attached to the lacrimal bone
What is the purpose of the medial check ligament?
Prevent over action of the medial rectus
What is the purpose of the lateral check ligament?
Prevent over action of the lateral rectus
What is the lateral check ligament?
Transverse dense CT that is an expansion of the sheath of the lateral rectus, attaches to the zygomatic bone
What is the orbital septal system?
Web of interconnecting CT septa, organizes the orbital space surrounding the globe, anchors and supports EOMs, nerves, and vessels
Which nerves pass through the orbit?
II, III, IV, V1, V2, VI
Which vessels pass through the orbit?
Ophthalmic artery + branches, superior and inferior ophthalmic vein + branches
What are the EOMs?
Medial, lateral, superior and inferior Recti muscles and superior and inferior obliques
What are the eyelid retractors?
Levator palpebrae, muller’s muscle, capsulopalpebral fascia
What is orbital fat?
Adipose tissue filling space not occupied by orbital structures, predominant tissue in the orbital apex
What is the role of orbital fat in the orbital apex?
Surrounds the optic nerve, separating it from the EOMs, separates the muscles in the orbit from the orbital walls
What is the role of orbital fat in the anterosuperior orbit?
2 fat pads are anterior to the levator aponeruosis (preaponeurotic fat pads) founde nasal and central, held in place by orbital septum
What is the role of orbital fat anteriorly and inferiorly?
3 fat pads are posterior to the orbital septum and anterior to the capsulopalpebral fascia, located nasal, central, and temporal, held in place by the orbital septum
