Orbit

Question 1

Orbit roof

Answer 1

frontal, and lesser wing of sphenoid

Question 2

Orbit lateral wall

Answer 2

Greater wing of sphenoid bone, and zygomatic

Question 3

Orbit medial wall

Answer 3

sphenoid, maxillary, lacrimal, ethmoidal

Question 4

Orbit floor

Answer 4

Zygomatic, maxillary and palatine

Question 5

Lamina papyracea

Answer 5

paper thin play covering ethmoidal air cells. entry of infection from ethmoidal sinus

Question 6

Optic forman

Answer 6

optic nerve
ophthalmic artery

Question 7

Superior ophthalmic fissure (SOF)

Answer 7

Superior: CN 4 + superior ophthalmic vein + lacrimal and frontal nerves (CNV1)

Inferior: CN 3 + 6 + nasociliary nerve (CNV1)

Question 8

Inferior orbital fissure (IOF)

Answer 8

inferior ophthalmic vein
infraorbital nerve (CNV2)
Zygomatic nerve (CNV2)

Question 9

Common tendinous ring (Annulus of Zinn)

Answer 9

origin of recti muscles
through: CN 2, 3 and 6 + nasociliary nerve

Question 10

Thyroid eye disease phases

Answer 10

Active inflammatory phase
Inactive fibrotic phase

Question 11

Thyroid eye disease risk factors

Answer 11

Smoking
Female

Question 12

What causes eye lid retraction in TED

Answer 12

Overstimulation of Muller muscle

Question 13

Complications of glycosaminoglycan deposition into EOM in TED

Answer 13

1. Restrictive myopathy
2. Exophthalmos - dry eyes and exposure keratitis
3. Fibrosis of levator palpebrae
4. Optic neuropathy (compression)
5. impaired venous drainage - conjunctival and periorbital oedema

Question 14

Clinical features of TED

Answer 14

1. Proptosis
2. Lid retraction (Dalrymple sign)
3. Lid lag on downward gaze (Von Graeffe sign)
4. Staring apperance (Kocher sign)
5. Restrictive myopathy: IR>MR>SR>LR

Question 15

TED investigations

Answer 15

TFTs
CT/ MRI orbit
Visual field testing

Question 16

Orbital mucormycosis

Answer 16

Fungal infection, gradual onset
Immunocompromised
Fx: orbital swelling and signs of orbital cellulitis, necrotic black eschars over the nose or palate

Question 17

Orbital cellulitis Ix and Mx

Answer 17

CT scan
IV abx

Question 18

Preseptal cellulitis mx

Answer 18

Oral abx

Question 19

Rhabdomyosarcoma

Answer 19

Most common primary orbital tumour in children

Question 20

Optic nerve sheath meningioma associated with

Answer 20

NF2

Question 21

Optic nerve glioma

Answer 21

NF1

Question 22

Direct carotid-cavernous fistula

Answer 22

High flow, between internal carotid and cavernous sinus directly

fx
- pulsatile proptosis
- conjunctival chemosis
- whooshing sound in head
- visual loss, ophthalmoplegia, raised ICP

Question 23

Direct CCF Ix and Mx

Answer 23

Ix: MRA
Mx: transarterial repair

Question 24

Indirect carotid cavernous fistula

Answer 24

Low flow, between meningeal branches of the internal/ external carotids and cavernou sinus

spontaneous in hypertensive women

Question 25

Cavernous sinus thrombosis

Answer 25

Due to spread of infections from para-nasal sinuses, ear or orbital cellulitis

Fx: proptosis, CN3, 4 and 6 palsy, reduced VA,
nausea, vomiting, rapid onset headache, chemosis

Mx: iv abx, steroids