Orbit/Lids/Adnexa Flashcards
<p>What are the dimensions of the adult orbit?</p>
<p>40mm W x 35mm H x 45mm D</p>
<p>What orbital bones make up the roof of the orbit?</p>
<p>Frontal andSphenoid (lesser wing)</p>
<p>What orbital bones make up the lateral wall?</p>
<p>Zygomatic andSphenoid (greater wing)</p>
<p>What orbital bones make up the floor?</p>
<p>Palatine, Maxillary, Zygomatic</p>
<p>What orbital bones make up the medial wall?</p>
<p>Sphenoid (lesser wing), Maxillary, Ethmoid, Lacrimal</p>
<p>Orbital length of the optic nerve? Intracanalicular length of the optic nerve? Intracranial length?</p>
<p>25-30mm, 9mm,16mm</p>
<p>What structures pass through the superior orbital fissure outside the annulus of Zinn?</p>
<p>Lacrimal (V1)</p>
<p>Frontal (V1)</p>
<p>Trochlear n. (CN IV)</p>
<p>Superior ophthalmic vein</p>
<p>"LFTS"</p>
<p></p>
<p>What structures pass though the superior orbital fissure within the annulus of Zinn?</p>
<p>Sup. division of CNIII</p>
<p>Nasociliary (V1)</p>
<p>Inf. division of CNIII</p>
<p>Abducens (CNVI)</p>
<p>"3N3 is6"</p>
<p>What structures pass through the optic canal?</p>
<p>Optic Nerve (CNII)</p>
<p>Ophthalmic artery</p>
<p>What structures pass through the inferior orbital fissue</p>
<p>Infraorbital neurovascular bundle</p>
<p>Inferior ophthalmic vein</p>
<p>Zygomatic nerve</p>
<p>Ganglionic branches (from pterygopalatine ganglion to maxillary n.)</p>
<p>What is the arcus marginalis?</p>
<p>Fusion of the orbital septum and periosteum at the orbital rim, fuses with dura covering ofoptic nerve</p>
<p>How many fat pads are in the upper eyelid?</p>
<p>2 - nasal fat pad (smaller and paler), and central</p>
<p>How many fat pads are in the lower eyelid? Which fat pads are separated by the inferior oblique?</p>
<p>3 - the IO separates nasal and middle fat pads; the lateral fat pad is smaller and more inferior</p>
<p>What is the innervation of the lacrimal gland?</p>
<p>Secretomotor - superior salivary nucleus of CN7</p>
<p>Sensory - CNV</p>
<p>Sympathetic - fromsuperior cervical ganglion</p>
<p>Whereare the glands of Wolfring found?</p>
<p>At the superior edge of tarsus</p>
<p>Where are the glands of Krause found?</p>
<p>In the fornices</p>
<p>Name the 3 anatomic parts of the orbicularis oculi</p>
<p>Pretarsal</p>
<p>Preseptal</p>
<p>Orbital</p>
<p>Where does the orbital septum fuse in non-Asian eyelids?</p>
<p>To the levator aponeurosis 2-5mm above the superior tarsal border</p>
<p>Where does the orbital septum fuse in Asian eyelids?</p>
<p>To the levator aponeurosis between the eyelid margin and the superior border of the tarsus</p>
<p>How long are the muscular and aponeurotic portions of thethe levator palpebrea?</p>
<p>Muscular = 40mm</p>
<p>Aponeurotic = 14-20mm</p>
<p>Where is Whitnall's tubercle located and what structures are attached to it?</p>
<p>11mm inferior to the FZ suture and 4-5mm posterior to the orbital rim;</p>
<p><strong>4 L's:</strong></p>
<p><strong>L</strong>ockwood suspensoryligament</p>
<p><strong>L</strong>ateral rectus check ligament</p>
<p><strong>L</strong>ateral palpebral ligament</p>
<p><strong>L</strong>evator aponeurosis</p>
<p>(Whitnall's ligament does NOT attach to the Whitnall's tubercle; actually inserts to trochlea medially and the FZ suture temporally)</p>
<p></p>
<p></p>
<p>From where does Muller's muscle originate? Where does it insert? What is it's length? How much does it raise the eyelid?</p>
<p>Origin: undersurface of levator at level of Whitnall's ligament</p>
<p>Insertion: superior border of tarsus</p>
<p>Length: 12-15mm</p>
<p>Action: raises eyelid 2mm</p>
<p>What are the lower eyelid retractors?</p>
<p>Capsulopalpebral fascia (analogous to levator aponeurosis), inferior tarsal muscle (analogous to Muller's), Lockwood's suspensory ligament</p>
<p>What are the heights of the superior and inferior tarsal plates?</p>
<p>10mm and 4mm respectively</p>
<p>Which limb of the medial canthal tendon is more important for appearance and function?</p>
<p>Posterior limb (attaches to posterior lacrimal crest), maintains apposition to the globe</p>
<p>What does the grey line demarcate?</p>
<p>Muscle of Riolan aka border of pretarsal orbicularis</p>
<p>What is the arterial supply to the upper eyelid?</p>
<p>ICA --> ophthalmic artery --> superior marginal arcade</p>
<p>What is the arterial supply to the lower eyelid?</p>
<p>External carotid artery --> facial artery --> angular artery --> inferior marginal arcade</p>
<p>What isthe pretarsal venous drainage pathway?</p>
<p>Medially: Angular vein</p>
<p>Temporally: superificial temporal vein</p>
<p>What is the post-tarsal venous drainage?</p>
<p>orbital vein, facial vein, pterygoid plexus</p>
<p>What aspect of the face drain to the submandibular nodes?</p>
<p>Medial 1/3 of upper lid</p>
<p>Medial 2/3 of lower lid</p>
<p>What aspect of the face drains to the preauricular nodes?</p>
<p>Lateral 2/3 of upper lid</p>
<p>Lateral 1/3 of lower lid</p>
<p>What are the lengths of the canalicular system?</p>
<p>Pucta: 2mm</p>
<p>Canaliculus: 8mm</p>
<p>Lacrimal Sac: 10mm</p>
<p>Nasolacrimal duct: ~15mm</p>
<p>Where is the weakest area of the orbit?</p>
<p>Posterior medial floor (blow out fracture)</p>
<p>What is a tripod fracture?</p>
<p>Fracture of the zygomaticomaxillary suture, zygomaticofrontal suture, and the zygomatic arch + the orbital floor</p>
<p>What bone is involved in all LeFort fracture?</p>
<p>Pterygoid plate</p>
<p>What is a LeFort I fracture?</p>
<p>Low transverse fracture of the maxillary bone above teeth, no orbital involvement</p>
<p>"floating palate"</p>
<p>What is a LeFort II fracture?</p>
<p>Pyramidal fracture of nasal, lacrimal and maxillary bones, involves superior medialwall or maxilla (orbital floor)</p>
<p>"Floating maxilla"</p>
<p>What is a LeFort III fracture?</p>
<p>craniofacial dysjunction, through ZF suture, orbit, nose, ethmoids</p>
<p>"Floating face"</p>
<p>What are the stages of globe degeration?</p>
<p>1. atrophia bulbi without shrinkage</p>
<p>2. atrophia bulbi with shrinkage</p>
<p>3. Phthisis bulbi (disorganization)</p>
<p>increased risk of malignancy, get bscan annually</p>
<p>Most common fungal orbital infection?</p>
<p>Phycomycetes</p>
<p>What are the findings of mucormycosis?</p>
<p>non-septae, large branching hyphae;</p>
<p>invasion of blood vessels w/ thrombosis and necrosis</p>
<p></p>
<p>What is the treatment for mucormycosis?</p>
<p>Surgical debridement, IV amphotericin B</p>
<p>Aspergillosis findings & treatment?</p>
<p>Septate, branching hyphae</p>
<p>Disseminated vs Local forms</p>
<p>Treat with surgical debridement, amphotericin B, flucytosine, rifampin</p>
<p>What causes dengue fever and how does it present?</p>
<p>Flavivirus</p>
<p>75% present with eye soreness and pain with movements</p>
<p>What are the most common presentations/locations of orbital pseudotumor?</p>
<p>1. Myositis (involves muscle AND tendon)</p>
<p>2. Dacryoadenitis</p>
<p>3. Scleritis</p>
<p>4. Orbital Apex</p>
<p>5. Diffusely thoughout orbit</p>
<p>What are the laboratory findings for orbital pseudotumor?</p>
<p>1. Eosinophilia</p>
<p>2. Elevated ESR</p>
<p>3. +ANA</p>
<p>4. CSF pleocytosis</p>
<p>Treatment for orbital pseudotumor?</p>
<p>steroids 1mg/kg prednisone, slow taper due to chance of recurrence; if no response, can consider radiation or immunomodulatory therapy (cyclosporine, MTX, cyclophosphamide)</p>
<p>When does orbital pseudotumor warrant work-up for systemic vasculitis or lymphoproliferative disordersz/</p>
<p>Simultaneous bilateral orbital inflammation in adults</p>
<p>(In children, ~1/3 are bilateral and rarely associated with systemic disorders)</p>
<p>What arethe histological findings for orbital pseudotumor?</p>
<p>pleomorphic cellular infiltrate consisting of lymphocytes, plasma cells, and eosinophils with variable degrees of reactive fibrosis</p>
<p>When to biopsy for orbital inflammation?</p>
<p>Isolated inflammation of the lacrimal gland</p>
<p>How does sclerosing orbital pseudotumor differ from NSOI?</p>
<p>Fibrosis of orbit and lacrimal gland</p>
<p>Slow insidious onset, pain less common, eye white and quiet</p>
<p>Less responsive to steroids</p>
<p>A-scan: low reflectivitiy (both lymphoma and orbital pseudotumor)</p>
<p>associated with retroperitoneal fibrosis</p>
<p>What is the most common cause of proptosis?</p>
<p>Thyroid eye disease</p>
<p>What is the most common clinical manifestation of thyroid eye disease?</p>
<p>Lid retraction</p>
<p>What is von Grafe's sign?</p>
<p>Lid lag on downgaze in thyroid eye disease</p>
<p>What would you find on pathology in thyroid eye disease?</p>
<p>patchy infiltrates of lymphocytes, monocytes, mast cells and fibroblasts; enlargement of muscles</p>
<p>What muscles are typically involved in thyroid eye disease?</p>
<p>IMSLO = Inferior > medial > superior > lateral > obliques</p>
<p>(tendons are usually spared)</p>
<p>In what order do you perform surgery for thyroid eye disease?</p>
<p>Orbital decompression --> strabismus --> eyelid surgery</p>
<p>Requirements before strabismus surgery in TED?</p>
<p>stability for 6 months</p>
<p>avoid if anterior inflammation is present</p>
<p>Prefer recession over resection</p>
<p>What are the common findings of sarcoidosis (in the eye)?</p>
<p>Panuveitis (often bilateral)</p>
<p>Thickened Descemet's membrane, band K, nummular keratitis, deep stromal vacuoles</p>
<p>pars planitis</p>
<p>chorioretinitis</p>
<p>orbital apex syndrome</p>
<p>ptosis</p>
<p>conjunctivitis</p>
<p>dacryoadenitis</p>
<p></p>
<p>Pathology for sarcoid</p>
<p>Non-caseating granulomas</p>
<p>Langhans' Giant Cells</p>
<p>Granulomatosis w/Polyagniitis findings</p>
<p>painful proptosis</p>
<p>reduced motility</p>
<p>chemosis</p>
<p>scleritis</p>
<p>keratitis</p>
<p>optic nerve edema</p>
<p>NLDO</p>
<p>GPA pathology</p>
<p>triad of vasculitis, granulomatous inflammation, and tissue necrosis</p>
<p>Differences between direct carotid-cavernous fistula vs dural-sinus fistula?</p>
<p>Direct c-c fistula: high flow, associated with head trauma; dilated corkscrew scleral/episcleral vessels, chemosis, elevated IOP, pulsatile proptosis, orbital bruit, dilated retinal veins; may develop ischemic maculopathy or RAO, enlarged C/D, CN6 palsy, anterior seg ischemia, blood in Schlemm's</p>
<p>Dural-sinus fistula: low-flow communication between meningeal branches of carotid artery and dural walls of cavernous sinus; often asymptomatic, associated with HTN, atherosclerosis, connective tissue diseases, may close spontaenously, need MRI/MRA</p>
<p>Dilated superior orbital vein on CT along with dilated corkscrew episcleral/scleral vessels, chemosis, orbital bruit, recent history of head trauma; diagnosis?</p>
<p>Carotid-cavernous fistula</p>