9. Orbital Clinical Anatomy

Question 1

Describe the anatomical problems of:
Acne Rosacea
Blepharitis
Hordeolum (Stye)
Chalazion

Answer 1

Acne Rosacea: sebaceous gland problem - eyelid inflammation - red eye
Blepharitis: chronic inflammation of lid margin (foreign body sensation, burning, redness)
Stye: pustule of hair follicles (ciliary glands)
Chalazion: plugging of Meibomian Glands (Tarsal Glands)

Question 2

Pathologies of Abnormal Eyelid Positioning

Ectropion vs Endotropion

Answer 2

Ectropion: lack of tendon support - red, dry eye
Entropion: too tight tendon - eye folds inward and rubs eye - scratches cornea, inflammation, high infection risk

Question 3

Etiology of Ptosis

Answer 3

1. Myogenic - Weak muscles (congenital or muscular dystrophy) - levator aponeurosis, Muller’s supratarsal muscle holds eyelid open
2. Neurogenic:
   Horner’s Syndrome: damage to symp chain = dysfx Muller muscle (superior tarsus muscle) = ptotic lid and miotic pupil (does not dilate in dim light)
   3rd Nerve Palsy: Weak levator = ptosis, no parasymp tone = dilated pupil (not constricted in bright light), pupil looks down and out (no extraocular muscle activation)

Question 4

Causes of Proptosis (3)

Answer 4

Eye Bulging!
1. Graves Orbitopathy: subacute, systemic THYROID disorder - double vision (worse in smokers); increased fat cells and extraocular eye muscles in orbit puse eye forward, can be compressive optic neuropathy
2. Vascular Congestion
3. Cellulitis:
Preseptal - lid inflammation - spares eye globe - tx as outpatient (Ex: DACROCYSTITIS - inflammation of lacrimal sac)
Orbital - life-threatening (can spread to brain), need to admit for IV ABx, due to sinus disease, hematogenous spread, penetrating wound, preseptal cellulitis, causes PROPTOSIS, pathway of spread from sinus: through anterior or posterior ethmoidal foramen (ex: ethmoiditis and subperiosteal abscesses)

Question 5

When would you use CT vs MRI for orbit imaging?

Answer 5

CT: BONE windows are good for lytic lesions, useful for lacrimal gland tumor, retinoblastoma

MRI: evaluating CNS tumors (Optic Nerve Glioma), good for SOFT TISSUE (capillary hemangioma)

Question 6

Trauma To Orbit = Fracture of Orbital Floor

where does it occur, what imaging would you do, what are the sx, what do you always check for

Answer 6

Occurs along suture lines (zygomaticofrontal line, zygomaticomaxillary line) or weak areas of medial orbital wall or floor
Imaging: CT better at bone than MRI
Sx: limited upgaze - due to damage to inf rectus on orbital floor (or fat on orbital floor pulls on inf rectus) - may cause double vision

In any orbital trauma - ALWAYS CHECK VISION